When uploading pictures to eBay, what is the largest picture URL returned
There are a few advantages to upload your pictures to eBay and have eBay host them, opposed to self hosting. You can see those differences in the following article,
Answer Title: Image Hosting: EPS Vs Self-Hosting
Answer Link: https://ebaydts.com/eBayKBDetails?KBid=1505
Now, when using eBay hosted pictures, in order to keep the service fast and easy to use, there are a few limitations. The main limitation being the image sizes returned. 800x800 (the _3 member image) is the largest image we currently show on ViewItem and is the largest image we return for use, depending on which PictureSet is supplied in the request. The UploadSiteHostedPictures call only returns back the list of static images that we generated as part of the upload.
The _# I am referring to is the end of the ebay URL you see in the UploadSiteHostedPictures response. For more details please see the UploadSiteHostedPictures call reference.