Layingback, thank you for the tip about P3Do. I have this tool and I have Thumbs 2000, which can do the same. Thumbs 2000 shows me all images included in zips. But not all have meaningful images included and I find it more comfortable to browse through the promotional thumbs, I have saved with the zips. Sometimes I save also sample renders of the object, if provided. And I try to keep track of the creators, the way Nancy proposed. Especially, when no readme is included as is in many cases of 3DS objects.