added the referall image

added the event referall iamge to the events folder
changed the black lines on the dollar bill

Removed the black lines on the image
Added new 'referral' event information.

# 50-character subject line
#
# 72-character wrapped longer description. This should answer:
#
# * Why was this change necessary?
# * How does it address the problem?
# * Are there any side effects?
#
# Include a link to the ticket, if any.