Same goes for me.
I just tried it myself, and the file browser is all kinds of messed up. Showing 0B files without any names, not properly listing directories, etc. The spray I was trying to import is in my ~/Documents folder, and getting there was not nearly as simple as it should be. Then when I selected the file (it's a .vtf already) I have no indication if it actually worked or not.
So after playing with it a little I found you can upload an image to spray by typing out the image location with the image name in the box where it says "name". You can't navigate to it graphically.
Can confirm non-spray-compatible files appear without a name or filesize, but I can however change sprays and dont need to type out the name - http://steamcommunity.com/sharedfiles/filedetails/?id=118926442
Confirmed on Linux Mint 14 as well.
In addition, if you actually try to browse your drive (Via clicking the up icon), it will usually only be three 0B files with a few exceptions... My Steam root for example, (The root path in which Steam was installed.) shows up correctly, and you can browse folders in it normally. Then every path above that folder only shows the folder that I came from and three empty files.
For example, the folder that contains my Steam folder shows "Steam" and three empty files, go up a folder and it shows the folder I was just in and 3 more empty nameless files. The very root folder of my drive "/" shows the items "bin", "hl2", "platform", "reslists", and "tf" folders.
If I type a path, it usually only shows up the three empty files again.
If I do manage to select a file however, I notice that .vtf files still don't show up, even when typing the entire path in manually. (Well, copypasting it anyway.)
The fix for the bad FileOpenDialog should be out sometime in the next week or so, not sure how much the delay will be though. There were a number of issues with this, I think I've cleaned everything up. You'll know you have the new version if the file type drop down no longer shows *.bmp on Linux (we only support .bmp on Windows).
Nothing extracted yet.
When I'm in team fortress 2 and i try to import an image to be able to spray on a wall or something it won't let me browse to an image and the files it does show shows that they are 0 bytes.