I have a solution where I will have 1 - 15 photos per record. When printed, each photo will take up 1/2 page, for a potential total of 7.5 pages. However, if I only have 2 photos, I don't want to print 7 pages of blank paper.

I've tried sliding, portals, etc, but I haven't found a way to do this....any ideas?

The best solution is to use a related file to hold the images -- that way you are not limited to a max of 15 and don;t have to worry about blank spaces etc. You'd print by finding the related records (with the images on them) and print form the related file.

It's strange that your empty container fields don't shrink. Are you sure that they are completely empty, and that you don't have something else on the layout that is preventing shrinking and sliding? Did you remember to check the 'reduce size of enclosing part' option?