Years ago I had some software that would take your image and recolour it according to the colours in another image. I can't remember what it was and anyway it probably wouldn't work on current OS. But it worked well years ago so I am hoping there is something similar available now. I have searched and searched but it's like playing a text adventure game - I am not really sure what to type in to Google to find it.
Any ideas for a program to recolour an existing image, ( not just one colour in the image?) Or a plugin for an existing program. Or a program to edit the HEX files of each color to change them (I'm not even sure if that is possible). I'd prefer not to have to get Photoshop just to do this one thing. For a Mac if possible.
Thanks for any help.