Hi IA. I think I know what you mean -- when you delete your listing from the Listings Folder, you're hoping that the associated images would be deleted from the Image Folder as well.
That won't work. The only way you can delete images is either manually, or by using the Deletion Wizard.
I do have a suggestion that I use -- what you could do is make an Images Folder of the images you post for Listings of a particular day or of a particular type. When I delete all the Listings for that day (or type), I can also delete the Images Folder I made for the associated images. So at least that way, you can delete quickly, in bulk. An entire folder at a time.
The only problem is that you might have some images you want to save from the Image Folder you want to delete. In that case, be sure to move the images you want to save before you delete.
Auctiva, by the way, saves your images for a week after you delete them. So if you ever delete an entire folder by mistake, you have a week to correct the error. Deleted images are in your Deleted Images folder.