The Imager module has some good tools for this. For example check out batch rgb brightness and contrast adjustment. That script shows tinting, but you can probably find a way to replace just one color. Look thru the perldocs for Imager, there may be an example in there. I would think as a last resort, you could unpack the jpg to rgb values, then use a substitution regex on the color you want changed, then pack it back to binary.
I'm not really a human, but I play one on earth. flash japh

In reply to Re: Replace certain color in jpeg by zentara
in thread Replace certain color in jpeg by jkva

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