Superbuy, Pandabuy and Cssbuy publish all qc photos of all items that get to their warehouse. They are even categorized by size and color.
The free service qc.photos combines these different agents on a single site, which makes it really easy to find almost any qc picture in existence, by pasting the link to the item.
Just to repeat that: This site lets you view all qc pics from anyone who's buying anything on one of the three major sites. That's an incredible power we never had before.