For my eBay auctions/swap listings I always have a plain white background, with no shadowing in the picture. High lighting with flash usually works best for me, but you have to figure out an angle in that lighting where the flash doesn't reflect off any clear plastic in your picture.
Also, as others have mentioned the length/width is off. I open the pic in paint, and when I resize I make sure that both ratios are the same. From a full-size picture I resize to 35 and thats usually a great size picture for makeup. :]