You need a host that has php and GD though, that's the only way to do it that I know of. Maybe there's a way to do it with cgi (some free hosts have cgi) but even then there's no way of using a .htaccess to make .jpg act as .php.
This article shows the concept of it, but the code makes the sig change instead of text. I might change it though since that code can be simplified much more.
Archived topic from Iceteks, old topic ID:1867, old post ID:15544