> Now, people looking at those pictures may be sexualizing these images in the head

No, it's not only on their head. It's written right underneath the photos by redditors, ie: "my d* is so hard right now". So the picture by itself may be harmless, but the post as a whole puts children in a highly sexualized context.

To make matters worse, threads sometimes include links to fully illegal material on some download server. The bikini photos sometimes are just the thumbnail...

I doubt that's the case with Toddlers & Tiaras.