efficient way to compare 2 images?

[mnrvovrfc]

Nice try, only cheating with alpha channel. There are 256 discrete values for red, green and blue with a very large permutation and even if one of the registers from one file is 4 values apart from the other.

Change your code to add and/or subtract values from one register from one point, and do it to a few thousand points. The comparison for equality then will fail.

This is an interesting use for "POINT()" because in Freebasic the alpha channel has to absolutely be stripped out to do simple comparisons by 32-bit color.