The internet isn't very good at context. Often, we're given a pic of something with a blurb that's supposed to explain it, but without the wider view, it's hard to know what's actually going on.
It's part of why it's become a thing on Reddit to use a banana for scale when sharing something. The other part of why is because bananas are funny.
Comparison pics are neat because they are the fact and the context all rolled into one.