Click on a thumbnail so you can see the pic full-size. Partway down the screen, you should see a tick-box for "Delete photo?" and a "Submit" button. Just highlight the tick-box and press submit and you'll remove the photo from your gallery.
Hope this helps
Rowan
BEWARE OF THE FEW...
As I grow older, I regret to say that a detestable habit of thinking seems to be getting a hold of me. - H. Rider Haggard