here's my console utility to copy graphics. it can load paletted png or pcx file, and writes .new.png files. use it like this:
zgfxcopy.exe Item.png destx desty Item.pcx srcx srcy
here, "Item.png" is destination file, "Item.pcx" is source file, "dest" and "src" are destination and source coordinates in pixels, respectively. it will create "Item.new.png" file with 16x16 tile copied, and will try to do color translation for you.
dunno if it will work right with comm. pngs, tho: for some unknown reason comm. fork has palette written backwards, and color translation code may be confused by that.