Problem w/ 4chan

I can't make a new Thread in /wallpapers, says I need to upload an Image but refuses mine.
How come, how to use right?

Y'need better English for a start. And maybe your files have a resolution too big for /w/? Or maybe the size is too big? If it's neither of those, then basically, your PC is shit.

ddddddddddddd

- Resolution is less then anything I ever posted
- Filesize is below 200kb

- My PC is not shit for I play Crysis in Medium @ 1280x1024 on it without Problems.

And no, the Filetype is correct PNG, GIF and JPG. (FYI tried with conversion to all 3 Filetypes w/o winz)