Upload to iAd workbench fails

I have created a series of ads to promote a new iBook and have no errors in iAds Producer, but when I try to upload it to iAd workbench I get the following error: "shared-background@3x.jpg - Image format: is not supported." This is a .jpg that iAds producer has made and not one that I imported into the program, so I saved the package to the desktop and found "shared-background@3x.jpg" in the finder. It is only an alias and not a real file, so I know that there's something wrong but I can't seem to figure out if there's anything I can do about it since it's a file that iAds producer has generated.

Any ideas?