Today I upgraded to Ubuntu 13.10 from 13.04. It looks good. I didn't test Gimp Image Editor on the 13.04 version but I just tested the 13.10 version with a painting with Gimp and when I tried to upload the file to facebook it tells me that this is an invalid image.
I have an older laptop with ubuntu 12.04 and have the same Gimp installed in it. With the 12.04 version I have plenty of extensions for filing the images that I do on gimp and can upload them to facebook. I noticed that the 13.10 version has only a few extensions for saving a file from gimp.
Which extension should I use to save a file that facebook will accept in this 13.10 version?