how do i replace color to transparent?

something like this:

set effect "ReplaceColor" parameter rgb(248,0,247) to rgb(transparent)

Use Opacity as workaround

Well opacity works well for the entire sprite as a whole. If a specific colour needs to be targeted C2 doesn't have native support for such an action. Though I think it would be helpful. However we are fortunate to have such a large number of talented js coders :)

You can check out these to see if they are helpful.

scirra.com/forum/behavior-sprite-effects-inject-text-on-sprite_topic51516_page1.html

scirra.com/forum/plugin-canvas_topic46006.html

There is software available to do this for you, then you can download the sprites into C2. I'm OK with C2 not supporting this as it's a largely obsolete technique.

thank you very much for the help, I'm remaking an old game but has more than 6,000 sprites with a pink background, looking for that function, I thank you again.