'Chakster', I mainly use eBay because I have for so long. I attempted to use Discogs some time ago as a buyer and would find 20 or 30 listings for an LP title and 1 picture.
@arisonabob
Picture is on release page, anyone can change this picture or add another in better quality (everyone is a contributor). Seller don't have to upload pictures in his listing since there is a picture uploaded by others on release page, but seller must check deadmarks etc to list exact pressing of the release. Picture can be emailed to the buyer by request, link to a picture can be in the seller's item description if needed. They do not block email contact sharing in discogs messenger (ebay block everything). Listing is free, sales fee is 8% (only if you sold something).
Purchased a couple of titles and found the grading to be extremely poor. Returning the item was a nightmare too. Because it's free (I think it's still free), there are just too many listings to go thru and just searching a specific issue was also a negative. It's been many moons since this happened so I may look again.
Every buyer is protected by paypal buyer's protection and refund is guaranteed. Feedback system is the key to buy from good sellers with accurate grading.