Add PNG image support
This partly addresses #6500 by adding an \image
markup command that supports PNG in addition to EPS. PNG works in Cairo only.
I need to test it more, but it seems to work fine so far.
I also wonder which is better between a generic \image
command and a \pngfile
command next to \epsfile
(keeping in mind that we may want to add JPEG, and maybe even SVG someday).
Edited by Jean Abou Samra