Steps to reproduce:
- Open the new e-mail editor.
- Insert an inline image.
- Save the e-mail.
- Close the e-mail.
- Open the e-mail from the drafts folder. (It should be opened in the editor.)
- Open a separate new e-mail.
- Copy/cut the image from the draft e-mail into the new e-mail editor window.
Result: the image is pasted as a black rectangle symbol indicating that there is a problem of some sort. The image can still be pasted into other programs without problems.
This might also apply to “.eml” files that are opened and other situations.