One problem with my FP gallery was some of my images were $20, some were $12, some were $10 and some were $8 and I wanted them all to be one price (lower). FeaturePics only lets you arrange pricing by % changes - so a 50% change still left me with 10, 6, 5, 4.
Heres the trick:
Go in & set your pricing to 10%. This should reduce everything pretty well. Do that same thing one more time - recalculate with 10% AGAIN.
The minimum on FP is $1 so ALL of your images will now be $1 (20-2-.20=1) If your images were over $100 to begin with, you may have to do this 3x instead of 2x.
Now that theyre all $1, adjust UP however high you want (400% = $4).
Done! Sweet, fast trick!