Here we go again.......
Close the photo app. Double click the home button, a bar should open up at he bottom of the screen, touch and hold the photo app icon in the bar, a minus sign should appear in the top left hand corner, touch it to close the app completely.
Now, press the home button once and open the photo app when the home screen reappears, see if you can open the image now.....if not try this.....
Press and hold the on/off button until the red slider appears, slide to off. Give it 10 seconds and restart your iPad (if it doesn't start press the on/off and home buttons together then restart). Try to open the photo again to delete......if that doesn't work......
We'll try something else!
The Archangel