It's a URL. Not something that is unusual. Doesn't matter if it were a url or a really long word. Firefox handles it just fine. IE and Chrome does not. If there isn't a way to force the code to be handled the same, then so be it.
Usually though browser issues have to be addressed in the browser.
Usually what I tell most people that try and enter one huge long string is do not do it. Because your not really talking about software here. Your talking about a browser issue as different browsers may operate differently on how they handle that. Normally if you print one huge long thing it is going to wrap at the first space it finds which means on most browsers its going to cause a breakout.
parsing links how vb does it is what convert_markups does and is already called but again not sure how your doing your field as you have not told me so not sure how to respond. You never told me what variable the field is when I asked so I assumed maybe one of the regular category extra fields.
Maybe let me take another guess custom fields line 270 of showphoto.php try making it this
wordwrapping is handled by browser I see many threads on the internet about this and IE9
It is a browser bug nothing I have said works those real long urls of yours are simply not going to break in IE9.
I have tried PHP wordwrap and even a CSS word-wrap: break-word; statement in your body of the page and no matter what IE9 is bad so this is as I said a browser bug. The browser is not following the php coding or the css coding.