This may not be a bug, but a limitation. Images can be created dynamically. For example a link like:
http://mydomain.com/image.php?a=1&b=2the output of which could be an actual gif/png image. This is common for charts and graphs on stock market sites.
e.g.
http://cchart.yimg.com/z?s=mrk&c=^dji&a=v&p=s&t=1y&l=on&z=m&q=l [img]http://cchart.yimg.com/z?s=mrk&c=^dji&a=v&p=s&t=1y&l=on&z=m&q=l[/img]
The board software seems to only want regular expressions that end in gif/jpg/png. Does anyone know how to fix this limitation?