The screenshot applet accepts the filename "invalid->filename.jpg" without error mesage or blocking (like it does for names containing e.g. "*"). The issue shows a link in the "File Attachment" box, however, clicking the link brings up an error message:
HTTP Status 404 - Could not find specified attachment: d:\jira35\attach\ELERT\ELERT-3\23540_invalid->filename.jpg (The filename, directory name, or volume label syntax is incorrect)
The screenshot is not shown and the file does not exist.