Render images directly in terminal (if supported natively)

[d0c-s4vage]

Describe the Feature Request
Many terminals are starting to support graphics protocols that enable us to render images directly in the terminal.

Terminal	Environment	Images support	Protocol
uxterm	X11	yes	Sixel
mlterm	X11	yes	Sixel
kitty	X11	yes	Kitty
wezterm	X11	yes	IIP
Darktile	X11	yes	Sixel
Jexer	X11	yes	Sixel
GNOME Terminal	X11	in-progress	Sixel
alacritty	X11	in-progress	Sixel
st	X11	stixel or st-sixel	Sixel
Konsole	X11	yes	Sixel
DomTerm	Web	yes	Sixel
Yaft	FB	yes	Sixel
iTerm2	Mac OS X	yes	IIP
mintty	Windows	yes	Sixel
Windows Terminal	Windows	in-progress	Sixel
RLogin	Windows	yes	Sixel

See the source of this list here: https://github.com/chubin/wttr.in/blob/master/doc/terminal-images.md

Example Markdown

Normal images in markdown should be rendered (via a custom Sixel/IIP urwid component) directly in the terminal.

Screenshot/Wireframe

Additional notes

[d0c-s4vage]

A few notes:

• Python bindings exist for libsixel and the Sixel image format (https://github.com/saitoha/libsixel)