I added an upload zone with Black as available color, and that colors any png I put on that area, but when I do it in the fron end, the png logos keep their color. How do I limit the color for uploaded pngs as well? I mean, it's working for the ones I use in the Product Builder.
Sorry, there is no way of limiting the colors of uploaded images.
I have the same requirement/problem.
Fixed elements on the page can have a specific palette of colors. So can text. But not uploaded images.
I need the uploaded elements to match the fixed images and text, because everything will be printed in a single color.
Even better if the color linking feature worked across all items.
If you do need this feature, please make a feature request in the feature request forum.