Cannot delete some photos

On my iPhone 5 running 7.1.2, I cannot delete some of my photos. These are pics taken with the phone. When I go to "photos", then click on "photos" at the bottom, and then "select" , some photos that I select have the "trash can" grayed out. Others allow deletion. Any ideas?

If those photos are synced with iTunes, connect your device to your computer and then attempt to delete them from within iTunes.

It's a bug, should disappear automatically.