I did this on Picassa, the Google photo thing (tool, webpage? what do you call these things?) First, I worked out 14 different variations of the block in the pattern I am using (Highlight from American Patchwork & Quilting) and one by one took photos on my design wall, like this I didn't cut too much or more than necessary of the beautiful fabric and ruin any that I might later need in the quilt. Then I uploaded the photos from my computer into Picassa, cropped them manually so there was no other colour around them and made a simple collage. I printed that out and took it to a photocopy shop (HP ink costs a fortune here in Venezuela) and paid for 6 copies of my Collage. So then I had 6 X 15 (Picassa filled out the space in the collage with a repeat) = 90 blocks to cut out and play with, all for the price of 6 colour photocopies. This was especially useful as I am using big print fabric and big blocks which finish up 19" square. Also useful if like me you know what you want but cannot SEE it until it's done. If it's wrong I know it but I have then cut up the fabric to certain sizes and my choice for change is limited. I'm very excited about this as I can start working on this quilt for my sister much more confident of a good result.
I couldn't move the photos one by one in the collage which I think was lack of computer skills, there is a collage where you can move them around too but I would have been there much longer than down to the copy shop and back!