First, only image files in the formats .jpg, .gif and .png are allowed.
Then, make sure your picture not corrupted(non viewable), and try more different images to upload. if all failed, report it to us. You can download one photo from our site, and use it for test. Good luck!
Last, report the error to us with the error info.
Question: Failed to upload, no sid error?
Generally this error happens when your session is out of date. You need to do is to close your browser and sign in again.