I have a set of GIFs, each of which includes a rectangle in a particular
color, and now I need to change that rectangle in each file to be
another particular color. The rectangle is a different size in each
file. Is there a free or cheap app that will allow me to do one of the
following:
1. Accept a list of input files and two colors, and change every
instance of the first color to the second color in each of the files.
2. Open all the files at once, or at least in large batches; allow me to
select a paint color; select a paint tool; and then, boom boom boom,
click the rectangle in each of the graphics to paint it the new color.
