option 1 -> Convert them to gif ,upload it on any freebie sites and post the link here .
Option 2 -> Practice and become an expert in ascii drawings , then you will be appreciated in ascii uml world ( if it exists - at least i know the ascii star wars exist ! - telnet to { towel.blinkenglights.nl } for star wars on telent ..
Or try
http://www.gentleware.com/ : Poseidon for UML