kind of curious why they asked you to make something that you never made before. its like saying - can you make me a wedding cake or two... because your cookies are good.
and without them specifying what kind of abstract... well in any case, be sure to get a non refundable deposit first. and tell them you don't normally make abstract.
a quick fyi, the images you have up right now, will need be larger, and cropped clean without the watermark, or they won't print them.
---Mike Savad
MikeSavad.com