Trailing "/" not implicitly added to end of URI

I’m running a single mongrel instance with a registered DirHandler.

I cannot use relative paths in any HTML that is served (e.g.
“images/myimage.png”) unless there is an explicit “/” at the end of my
URI. So is available for purchase - (image works) is available for purchase - (image does not work)

Is this a bug or was it designed this way. Is there an accepted way to
get this working?