If you are having trouble of this nature with editing files, you should start a new thread in the creation & customization forums. There are many players there with experience in both programs you mention.
edit: I use an old version version of PSP and just save in 256 color .pcx file format. When working with the files, you are probably changing them to millions of colors.
edit: I use an old version version of PSP and just save in 256 color .pcx file format. When working with the files, you are probably changing them to millions of colors.