Really neat! Every time I see this I'm reminded of what we lost from the 1990s, when xterm supported Tektronix 4014 emulation. Vector graphics right there via a tty interface! It wasn't terribly useful in practice but it could do some nice things with plotting.

https://iterm2.com/documentation-images.html

there is also sixel. https://github.com/saitoha/libsixel