The solution: empty the trash. The trash is designed as a safety net for those rare moments when you unintentionally delete an image. That's just the way it works. And to my knowledge there is no workaround.
Thanks for the quick reply, although I obviously knew I could empty the trash The problem is that the process takes longer that way..
Each and every drive that is connected to your computer, whether internal or external, and is formatted in the NTFS format has a Recycle Bin which is tied to the trash can on your desktop. No files got moved or copied to your internal drive. They just got placed in the Recycle Bin on the drive they were deleted from.
To bypass that you can set the Recycle Bin to Delete file directly bypassing the Recycle Bin. But I don't suggest you do that.
Just Right Click on the Trash Can, IE the Recycle Bin, and select "Empty Recycle Bin".
Thanks for the explanation and help!