Delete Picture
In most cases deleting or removing a picture from 'Projects', 'Exhibitions' and 'Exhibits' simply deletes the association with that item and does not actually delete the picture from the server. This is so the image can be used somewhere else.
To permanently delete a picture so you can replace with another picture go to 'Picture Library' area of your 'Control Panel'.
Hover over an image and click the rubbish bin / trash can icon to permananetly delete the image.