Most emulate an xterm, which didn't have support for graphics. (And xterm itself is emulating an even older TTY … with features bolted on…)
There are some escape sequences you can feed to some terminals, though, that emit graphics. "Sixels" are pretty well known for pushing graphics to a terminal, but they're not universally supported.
iTerm2, on macOS, has a means of escaping and then sending a PNG, which is then displayed, IIRC. (But it's unique to iTerm2, and IIRC iTerm2 identifies as an xterm so it's basically impossible to autodetect.)
