I agree that in those photos, the text is much too dark. I also feel that the background is too busy and/or the item for sale isn't shown large enough. Could you blur the background a bit? (I know this is a photographic "trick" but don't know how it's done.) You might also try the image "cropper" on the 2nd page of the listing process (this is actually a zoomer, rather than a cropper, as it doesn't actually do anything to your image).