For XBM and PPM formatted images, the `image` command in Tk allows you
to pass a `-data` option that would contain the image data in the same
format as you`d have in a file.
*Note:* The Tk plugin (http://www.scriptics.com/software/plugin.html)
and Tk8.0+ can read base64 encoded GIF data via `-data`, but this isn`t
available in Tk4.2- unless you get the excellent Tk plus patch
(http://home.wxs.nl/~nijtmans/plus.html) by Jan Nijtmans