Hello dutchman48 -
There is an issue with images imported from closed listings - at this time, eBay is only providing us with images slightly smaller than the minimum requirement for images when we import, so for these listings you would need to either resize your images (there is a tool for that in the edit images area of the Image Management page, or from the lister once an image has been added) or upload them again at the appropriate size. You may wish to upload new images as there is a chance that image quality would be reduced by enlarging images.
You can certainly only add a Header/Gallery image to your listings if you prefer, but please keep in mind that you will need to include at least these images in your listing to be able to get it to post to eBay. You will not be able to post a listing to eBay with no images as the Header (which is also typically used for the Gallery image) is a requirement for posting.