G G said: There's a lot more to visual quality of a graphic than the size. All else being equal, iIf you have the choice, its best to save as PNG. Jpgs lose quality each time you edit or save them, PNGs dont. That said, JPGs can be dramatically smaller and still look good, so if you're only saving it once and not editing it before uploading, a jpg works just as well and wont take up as much space in your library. I generally keep pngs as archive copies, and save them as jpgs if I'm posting them online (like in roll20's library). For this reason, it's good to use jpegs for static maps, which don't generally require transparency. Modular tiles frequently have transparent edges; many people assemble tiled maps in an image editor, save an editable copy, but export a jpeg for uploading to Roll20. The fewer the pieces, the better the performance. I generally save in PSD format, but TIFF is fine for saving layered, editable graphics.