If I try to upload an image from (say) http://example.com/test.png or http://upload.wikimedia.org/wikipedia/commons/thumb/a/ab/Japon-1886-32.jpg I get the following error message:
The file is corrupt or has an incorrect extension. Please check the file and upload again.
This error message should tell me what really went wrong: a HTTP error.
Version: 1.15.x
Severity: enhancement