I'd include screenshots, however this particular bug would prevent this

When trying to report an issue regarding subforums of "Other Mods" on the forum, I attempted to add an image. Here are my results:

=14pxMethod 1, pasting an image:
Start writing a post
Copy an image to the clipboard
Paste in the image using ctrl v

Expected result:
The picture should be added to the post

Actual Result:
The picture is displayed for a part of a second.
A green message says "File Successfully Uploaded"
A red message says "Incorrect server response" and the image disappears.

=14pxMethod 2:Using the picture button
Start writing a post
Take a Screenshot and save it
Hit the button to add a picture
Select "upload"
Choose the image from your harddrive
Click "Send it to the server"

Expected result:
The photo is uploaded and added to the post

Actual Result:
Image selection is replaced with the message "Invalid thumbnail file name"

We don't have the facility to directly upload images here, as detailed in the following FAQ.
What am I allowed to upload

Here's the relevant part concerning images.
"Please refrain from uploading other files, unless requested to do so. In particular, please do not upload image files (for example, screenshots) unless requested, or upload them to an external site and provide a link."

Hope this helps.

While I ask that images are hosted elsewhere to keep disk usage and bandwidth low, it does upload despite the pesky error message. If you click browse server and then the images folder, they are there. The error is on my list to resolve.