Intelligant file search for firefox

I want to use a grep like search routine in firefox's search file dialogue i.e. I want to click on 4chan's 'Search' buttan and be presented with a field where I enter 'cat' and I will be shown a list of files that have the pattern 'cat' somewhere in the filename. Any ideas on how to implement such a feature. Better yet, does anyone know an existing firefox extension that is able to do this?

Ok, you're all very funny. I would like to apoligize again for trying to be funny myself when I should have known I could never reach the level of your wit. Anyway >>21, I dont see what's retarded about my question apart from the typos - I want to use pattern matching when looking for a pic to upload. If this is stupid, please enlighten me and let me know teh reason.