You can convert an image to ascii art. First install using the aview which is part of aalib using homebrew. http://aa-project.sourceforge.net/aview/

> brew install aview

Make sure you have a graphics converter. Some use imagemagick, but I recommend graphicsmagick due to the simplicity of command. http://www.graphicsmagick.org/

> brew install graphicsmagick

Aview supports only pnm (graphics format). Now convert the image using graphicsmagick. I use png format, but you can use jpg or others.

> gm convert myimage.png myimage.pnm

And finally see it in ASCII

> aview s.pnm

 
Alternatively, consider using libcaca which seems to be better maintained. http://caca.zoy.org/wiki/libcaca