Image modification presets

[jkenlooper]

Add image modifications presets like a de-saturate colors to convert a puzzle image to be in gray scale. Could also transform the puzzle image to rotate it by 90 degree increments.
Image modifications would be applied to new puzzles being uploaded. They could also apply to puzzles that are being rebuilt.

More complex modifications could be to selectively replace larger areas that are a solid color to have randomly generated splotches in the same shade of color that they are replacing. This would make a puzzle that had a lot of blue sky have something that would be more interesting.