To be honest @highstrung, I don’t know. I assumed it was supposed to be based on the original release as that is what we do with Recording names, etc. But maybe it is the most common image? Or most recognised image?
I’ve been working on this Crass - Feeding of the 5000 and assumed the Release Group should be that original cover and not the more commonly recognised cover with a border. Every reissue of that album has changed what appears in the right hand margin. (Stands out well if you use @jesus2099’s must have FUNKEY ILLUSTRATED RECORDS)