Hi Donna,
If you go to the Images tab and select Manage Images, you'll see your photo library and there is a Delete option you use in combination with the selection check box next to each image. There is also a check box at the top of each page that can delete all images on the page (be careful of that one). When you use delete the image is placed in a Deleted Folder and retain for a week. You can access the Deleted Images and restore them from the "View Deleted Images" link on the main Images page.
I don't think an accidently deleted image would immediately "disappear" from an active listing due to the 7 day retention in Deleted folder.
Danno