I had a look at quite a few of your listings and the ones where there is no gallery photo, they are all nowhere near the minimum required size. Quite a few of the ones still showing are too small too, so don't be surprised if they disappear soon too. I think in this instance, you don't really have much choice but to redo all your photos so they are at least 500 pixels on one side. The most yours are showing at the moment is 300. Even if eBay "fix" the "glitch", it's not going to fix your problem.