I think I was misunderstood. when I said uncompressed .png I meant the way construct stores sprites in .cap file. At least the way I read on this forum, It stores image as uncompressed .png thus making .cap file pretty big when working with high res pictures.
I still don't understand what you're talking about... Construct stores images in PNG format in the .cap, which is compressed. I don't know what you mean by "uncompressed .png" because .png files are always compressed.