Thumbnails do not appear for images with spaces in the name

Thumbnails for images with spaces in their name do not appear at all. The thumbnail system seems to render the space as a '+' which results in a page not found error, whereas the actual attachments use '%20' which seems to work.

Workaroud:

As workaround users can browse through the attachments section (Tools > Attachments) of the page, and for the attachment you have a space on it (in example: my file.jpg), click in properties and change the file name (so for the my file.jpg you could rename it to myfile.jpg). The image should display fine after that.