<PAGE>
 

                                                                   EXHIBIT 10.16
                        
                        CONSULTING ENGAGEMENT AGREEMENT
         

This Consulting Engagement Agreement (the" Agreement") is made effective as of
May 14, 1998, (the "Commencement Date") between The Brenner Group LLC, a
California limited liability company, with its principal place of business
located at 20195 Stevens Creek Blvd., St. 110, Cupertino, CA 95014-2357
("Consultant") and Raster Graphics Incorporated, a Delaware corporation, with
its principal place of business located at 3025 Orchard Parkway, San Jose, CA
95134 ("Client").

                                   RECITALS

A.  Consultant is in the business of providing management services to client 
    companies in all areas of business operations.

B.  Client is in need of assistance in the form provided by Consultant.

C.  Consultant and Client desire to enter into a consulting arrangement upon the
    terms and conditions set forth herein.

NOW, THEREFORE, the parties hereto agree as follows:

1.  ENGAGEMENT:  Client agrees to engage Consultant under the terms of this 
    -----------
    Agreement, and Consultant agrees to accept such engagement. Consultant, or
    its representative shall be available to Client according to the time or the
    projects specified in Exhibit A, attached hereto and made a part of this
    Agreement by reference herein.

2.  TERM AND TERMINATION:  Consultant's engagement pursuant to this Agreement 
    ---------------------
    shall commence on May 14, 1998 and continue until September 30, 1998, unless
    terminated earlier, as provided herein (the "Term"). At the end of the
    Term, this Agreement shall automatically be extended for periods of three
    (3) months each, unless one party gives the other party one (1) month notice
    of their intent to not extend the Agreement. During the first five (5) days
    after the effective date of this Agreement, either party may terminate this
    Agreement with one day notice. Other than for the reasons described in
    Section 4, below, either party may terminate this Agreement during the Term,
    or any extensions thereof, by giving the other party one (1) month written
    notice of their intent to so terminate.

3.  COMPENSATION: As compensation for services rendered by Consultant pursuant
    -------------
    to this Agreement, Client shall pay Consultant the sum(s) as shown on
    Exhibit A, plus reimbursement for any expenses incurred on Client's behalf.
    If Consultant uses his automobile on Client's behalf, Client shall reimburse
    Consultant for actual miles traveled at the rate of $0.32 per mile. Client
    and Consultant agree that Exhibit A may be modified from time to time, and
    such modifications shall be made a part of this Agreement when executed by
    both parties.
<PAGE>
 
4.  PERSONNEL: Client and Consultant agree that Consultant is not in the 
    ---------
    business of providing a recruiting or placement service for permanent
    positions. However, if Client wishes to offer employment to any of
    Consultant's representatives, and if the representative wishes to accept
    such employment, Consultant has the right to invoice Client, and Client will
    promptly pay, a fee as shown in the following table:

<TABLE>
<CAPTION>

       ----------------------------------------------------------------------------
       <S>                                                 <C>   
       Period after the Effective Date of the Agreement     % of estimated first
                                                            year's compensations
       ----------------------------------------------------------------------------
       Within the first six (6) months                            50%
       ----------------------------------------------------------------------------
       Between seven (7) months and nine (9) months               40%
       ----------------------------------------------------------------------------
       After the commencement of the tenth (10th) month           30%
      ----------------------------------------------------------------------------
</TABLE>

5.  INVOICING AND PAYMENT: Consultant shall invoice Client as of the fifteenth 
    ----------------------
    and last day of each month for services performed pursuant to this
    Agreement. Client shall pay Consultant's invoice, in full, within five (5)
    business days of the date of Consultant's invoice. If Client does not
    pay Consultant pursuant to these terms, Consultant shall have the right to
    receive a retainer, as described in Paragraph 6, below.

6.  RETAINER: If Consultant has the right, pursuant to Paragraph 5, above, to 
    ---------
    receive a retainer form Client, and further, if Consultant requests such
    retainer, Client shall pay Consultant a retainer (the "Retainer") upon
    written demand from Consultant. Such retainer shall approximate Consultant's
    best estimate of one half month's worth of Consultant's charges working on
    Client's matters. Client agrees that such retainer shall be replenished to
    an amount equal to the following one half month's projected amount due for
    projected services during such period. Any retainer remaining shall be
    applied against the final invoice pursuant to this Agreement.

 .   STATUS: Consultant is engaged by Client as an independent contractor, and 
    -------
    not as an employee. As such, Consultant is solely responsible for and will
    make proper and timely payment of any and all taxes on amounts paid to him
    by Client, including, if applicable, estimated state and federal income
    taxes, self employment taxes, state disability insurance taxes and the like.
    Consultant will not receive or participate in any of Client's employee
    health insurance or any other employee fringe benefit programs, and
    Consultant will not be covered by Client's workers' compensation and other
    insurance policies.

<PAGE>
 


8.   PROPRIETARY INFORMATION AND INVENTIONS: Consultant understands that certain
     ---------------------------------------
     proprietary information of Client's may be disclosed to him during the term
     of this Agreement. Unless such information was known to him prior to such
     disclosure, or becomes part of the public domain, Consultant agrees not to
     disclose such information to third parties for a period of twenty four
     months, without prior written consent of the Client. Consultant
     acknowledges that, if requested by Client, he will sign an additional and
     separate Non-Disclosure Agreement with Client.

9.   NO AUTHORITY: Consultant does not have, and is not granted by this
     -------------
     Agreement, any express or implied right or authority to assume or create
     any obligations on behalf of, or in the name of, Client; or to bind Client
     to, or enter into, directly or indirectly, any contract, agreement or
     undertaking with any third party. If Client wishes to grant such authority
     to Consultant, Client shall issue such authority to Consultant in writing
     prior to Consultant taking any such action.

10.  INDEMNITY: Client shall offer indemnification to Consultant in a manner 
     ----------
     that is acceptable to both parties.

11.  MISCELLANEOUS: 
     --------------

   A. ASSIGNMENT: This Agreement may not be assigned by either party hereto 
      -----------
      without the prior written consent of the other.
     
   B. ADDITIONAL PERSONNEL: Consultant may use additional personnel to support
      ---------------------
      the requirements of Client under this Agreement. The additional personnel
      will only be used after Client has agreed in writing to: (a) such
      addition; (b) the compensation for such addition; (c) the term of such
      addition, and (d) such addition is made a part of this Agreement by an
      amendment to Exhibit A and executed by both parties.

   C. GOVERNING LAW: This Agreement shall be governed by and construed in 
      --------------
      accordance with the laws of the State of California.
<PAGE>
 
D.  NOTICES: All notices hereunder shall be in writing, and shall be deemed
    -------
    given upon personal delivery or upon placing in the United States postal
    service First Class delivery system, to the addresses set forth below:

    IF TO CONSULTANT:                        IF TO CLIENT:
       Richard M. Brenner                      Rak Kumar  
       Managing Director                       President & C.E.O.
       The Brenner Group LLC                   Raster Graphics Incorporated
       20195 Stevens Creek Blvd., St. 110      3025 Orchard Parkway
       Cupertino, CA 95014                     San Jose, CA 95134

    Either party may change its notice address by written notice to the other in
    accordance herewith. 

E.  AMENDMENT; ENTIRE AGREEMENT: This Agreement may be amended only in writing,
    ---------------------------
    and signed by both parties. This Agreement sets forth the entire
    understanding of the parties with respect to the subject matter hereof, and
    expressly terminates and supersedes any and all oral and or written
    understandings and agreements with regard to such subject matter.

F.  ATTORNEYS' FEES: If any action is brought hereunder, the prevailing party
    ---------------
    shall be entitled to reasonable attorneys' fees to be fixed by the court in
    such action.

G.  PARTIAL INVALIDITY:  If any provision of this Agreement is found to be 
    ------------------
    invalid by any court or other authority, the invalidity of such provision
    shall not affect the validity of the remaining provisions hereof.


IN WITNESS WHEREOF, the parties have executed this Agreement this 14th day of 
May, 1998, to be effective as of the fourteenth day of May, 1998.

CONSULTANT:                                         CLIENT:
----------                                          ------

/s/ Richard M. Brenner                                 /s/ Rak Kumar
--------------------------                          ----------------------------
        Signature                                            Signature

    Richard M. Brenner                                     Rak Kumar
--------------------------                          ----------------------------
          Name                                                  Name

     Managing Director                                    President & C.E.O.
--------------------------                          ----------------------------
          Title                                                  Title

   The Brenner Group LLC                            Raster Graphics Incorporated
--------------------------                          ----------------------------
         Company                                               Company

                                  Page 4 of 5
<PAGE>
 
                                   EXHIBIT A

THE ASSIGNMENTS SHALL BE DEFINED AS:
------------------------------------
 . Consultant shall assist Client by performing duties normally associated with
  the Chief Financial Officer of Client, including SEC report preparation for
  Client's signature and managing the day to day accounting and finance
  functions of Client's business.

 . Consultant shall assist Client in such other matters as Client may reasonably 
  request.

CONSULTANT'S RATES FOR SUCH SERVICES:
------------------------------------

<TABLE> 
<CAPTION> 

              -----------------------------------------------------------------
                       Consultant's Representative                    Rate
              -----------------------------------------------------------------
               <S>                                               <C>  
               1.  Kathy J. Bagby, or equivalent                 $155 per hour
              -----------------------------------------------------------------
</TABLE> 

IN WITNESS WHEREOF, the parties have executed this Agreement this 14th day of 
May, 1998, to be effective as of the fourteenth day of May, 1998.

<TABLE> 
<CAPTION> 

CONSULTANT:                                     CLIENT:
----------                                      ------
<S>                                             <C> 
/s/ Richard M. Brenner                            /s/ Rak Kumar 
------------------------------                  -------------------------------

    Richard M. Brenner                                    Rak Kumar  
------------------------------                  -------------------------------
          Name                                              Name

      Managing Director                                 President & C.E.O       
------------------------------                  ------------------------------- 
          Title                                               Title   

     The Brenner Group LLC                        Raster Graphics Incorporated
------------------------------                  --------------------------------
          Company                                            Company
</TABLE> 

                                  Page 5 of 5
<PAGE>
 


                                  EXHIBIT A-1


This Exhibit A-1 is hereby added to the Consulting Engagement Agreement (the 
"Agreement") between The Brenner Group LLC ("Consultant") and Raster Graphics 
Incorporated ("Client") dated as of May 14, 1998.  All terms and conditions of 
the Agreement and this Exhibit A-1 shall continue to have the same meaning as in
the original Agreement. The intent of this Exhibit A-1 is to provide for the 
additional compensation as described below.  This Exhibit A-1 is an addition to 
the Agreement, and Exhibit A in the Agreement shall remain in full effect and 
force.

Consultant's additional rates for services:
-------------------------------------------

 .   Client wishes to incentivize Consultant to continue to assist Client in the
    management of its financial affairs. To accomplish this, Client agrees to
    pay Consultant a fee, which is in addition to any other fees which
    Consultant is entitled to pursuant to the Agreement, as more fully described
    below (Additional Fee). Such Additional Fee shall be payable to Consultant
    during the Term, and any extensions thereto, or at any time within six (6)
    months of any termination of the Agreement if Client's business is sold or
    merged or is re-capitalized (the "Transaction").

    .  If the Transaction is $5 million or greater but less than $7 million,
       and occurs at any time prior to August 14, 1998, Consultant shall be
       entitled to an Additional Fee of $85,000, payable upon presentation of an
       invoice from Consultant to Client;
       
    .  If the Transaction is $5 million or greater but less than $7 million, and
       occurs after August 14, 1998, Consultant shall be entitled to receive an
       Additional Fee of $85,000 plus $17,000 for any month (or fraction
       thereof), up to a maximum Additional Fee of $170,000, payable upon
       presentation of an invoice from Consultant to Client;

    .  If the Transaction is greater than $7 million, and occurs at any time
       prior to August 14, 1998, Consultant shall be entitled to an Additional
       Fee of $100,000, payable upon presentation of an invoice from Consultant
       to Client;

    .  If the Transaction is greater than $7 million, and occurs after August
       14, 1998, Consultant shall be entitled to receive an Additional Fee of
       $100,000 plus $20,000 for any month (or fraction thereof), up to a
       maximum Additional Fee of $200,000, payable upon presentation of an
       invoice from Consultant to Client.

IN WITNESS WHEREOF, the parties have executed this Agreement this 22nd day of 
June, 1998, to be effective as of the fourteenth day of May, 1998.

Consultant:                                  Client:
-----------                                  -------

The Brenner Group LLC                        Raster Graphics Incorporated

/s/ Richard M. Brenner                       /s/ Rak Kumar
----------------------------                 ------------------------------
        Signature                                     Signature

    Richard M. Brenner                                 Rak Kumar
----------------------------                 ------------------------------
          Name                                          Name

     Managing Director                             President & C.E.O.
----------------------------                 ------------------------------
          Title                                         Title

                                  Page 1 of 1

<PAGE>
 

                                   EXHIBIT B

This Exhibit B is hereby added to the Consulting Engagement Agreement (the 
"Agreement") between The Brenner Group LLC ("Consultant") and Raster Graphics 
Incorporated ("Client") dated as of May 14, 1998.  All terms and conditions of 
the Agreement and this Exhibit B shall continue to have the same meaning as in 
the original Agreement. This Exhibit B is an addition to the Agreement, and 
Exhibit A and A-1 in the Agreement shall remain in full effect and force.

 .  The initial Term is hereby extended to November 13, 1998; and

 .  The Retainer paid by Client to Consultant shall remain in the possession of
   Consultant until the earlier of the sale of Client's business (in which case
   the Retainer shall be applied against the Success Fee owed to Consultant by
   Client) or eighteen months from the last day services are performed under the
   Agreement. Consultant shall apply the Retainer to fees for any additional
   services requested as a result of any litigation support for Client, or for
   any securities or other shareholder investigation which requires Consultant's
   attention;

 .  As of November 13, 1998, the Success Fee which is payable by Client to
   Consultant in the event of a Transaction valued at greater than $7 million is
   $160,000. After November 13, 1998, if Consultant is utilized by Client for
   less than 80 hours per month, the Success Fee shall be increased by $10,000
   per month, or portion thereof, instead of $20,000 per month. If Client
   utilizes Consultant for more than 80 hours per month, the success fee shall
   continue to increment by $20,000, as described in Exhibit A-1.
   

IN WITNESS WHEREOF, the parties have executed this Agreement this 28th day of 
September, 1998, to be effective as of the twenty eight day of September, 1998.

Consultant:                                        Client:
-----------                                        -------

THE BRENNER GROUP LLC                              RASTER GRAPHICS INCORPORATED

/s/  Richard M. Brenner                             /s/ Rak Kumar
----------------------------                       ----------------------
        Signature                                        Signature

    Richard M. Brenner                                  Rak Kumar
----------------------------                       ----------------------
         Name                                              Name

     Managing Director                               President & C.E.O.
----------------------------                       ----------------------
         Title                                             Title
                                  Page 1 of 1