There are no blockchains that store pictures.

Oh, but there are plenty of ways to store pictures on blockchains. Hive would be pretty decent for that. ASCII art, SVG or pretty much any vector format, procedural drawings, or even raw binary data in custom operations (they are limited to 8kB, but it should be enough for small pictures such as those monkey NFTs, you could also chain custom operations and compose picture out of their data later) or encoded in comment (where only block size is the limit).