re-installing wordpress from dashboard fixed it for me.
Thanks warezthief
when I try to upload a photo, I get the error mentioned before, but the image does get successfully uploaded to the following folder: /wp-content/uploads/2015/03
That makes me believe the issue is not with permissions on the server. I have however tried various permissions, including 777. All with the same result.
I guess I can try the default theme.
I have the exact same issue. I get the same error, even if the image is successfully uploaded to the ftp server. I have also tried uploading various sizes of images, in terms of size on disk as well as pixel size.
Anyone knows how to solve this issue?