: I have a question about SVGA cards.  I have a Tseng 4000 SVGA with 1MB
: memory and 3x 6-bit DACs as far as I know.  To display a 640x480x32768, 
: Now:  Can I display 640x480, 15bit/pixel bit-maps on this card?

You can. At the least, your _hardware_ is capable of supporting this mode.
I do know nothing about your video BIOS, though...

: If so, how?

Silly (but fool-proof ;) way: Install Windows with 640x480x32K colors
wideo driver and display your pictures under windows...

Cheese,