This generally happens when pasting an image from clipboard.
Sometimes there's no content in the clipboard... somehow (maybe windows just being windows)

An image upload preview with no image is displayed, and can still be uploaded, which ends up sending a 0kb file to the server.

These should probably not be attempted to be uploaded

Confirmed that this is a bug in Qt 5.9 for Windows. It actually causes a non-crashing access violation internally in the Qt code when certain types of formatted clipboard image data are pasted (QMimeData reads from 0xffffffff). Nothing I can do about the access violation right now -- I'm already doing every possible bad-data check that Qt lets me do in user code, so the bug will have to be fixed by Qt. Hopefully this is fixed in Qt 5.12.

In the meantime, I've added some post-checks where the upload button will be disabled if the image data given by Qt is a 0x0 image.

Please reopen this ticket if some image data is still not pasteable after Ripcord is upgraded to Qt 5.12.