Re: Illegal characters in file names
I just barely took a look at function fetch_image_info so maybe I'm wrong....
but... I think you should apply all your filters and replacements after this line:
270 $imginfo['saveas'] = $imginfo['filename'];
Remember, you want to save the file with restricted chars (a-zA-Z0-9_), NOT TO OPEN it. I mean, you won't change the name of the file uploaded to the temp folder, you just want to change the filename that is going to be saved.
I'me leaving right now, but as soon as I return I'll paste the corrected modification (if any).