Hi Waldi,
You should be able to repair the gallery images of these items via the following process:
1) Log into your eBay account and click on "My eBay"
2) Click on the item for which you'd like to change the gallery image.
3) Right click on the image you'd like to make your gallery image and click "Properties"
4) Copy the image URL...it begins with "http://..."
5) Click "Revise Your Item"
6) Click "Edit Pictures"
7) In the "Gallery Image URL” field, paste the copied URL over the existing one and save your changes.
I hope this helps=)
-Mike