efficient way to compare 2 images?

[madscijr]

@bplus I'm saying there's NO reliable test once you start blending two images together!

[b]madscijr [/b]asked why his code wasn't working -- it's because he was blending colors on a black background.  In his code, these two are a perfect match:

LINE (100,100)-(300,300), _RGB32(255,0,0), BF
LINE (300,100)-(500,300), _RGBA32(255,0,0,254), BF

Now, is 255 alpha and 254 alpha a color match?   Obviously not!

But once they're blended onto a 255 alpha image?  How different are they??

Yeah it just comes down to my ignorance that you need DONTBLEND for putimage to overwrite the image. I learned something new.