If your products images is showing as a generic polaroid image in a gallery view on eBay (see below) then it usually means that the image is in a CMYK format. eBay doesn’t supported images saved in the CMYK format so the image will need to be converted to RGB format.
To convert an image from CMYK to RGB, you can use tools such as Photoshop or http://www.cmyk2rgb.com.
More information on eBay picture guidelines can be found here.
If you have an image that still does not display correctly after checking all the guidelines eBay has set out. please try this link Fix Galley Image , you will need to login to eBay as the store owner, enter the eBay Item ID and follow the prompts.