I am getting the same issue as some other people have (with a child theme of Twenty Thirteen).
I have tried deactivating all the Plugins and also changing file permissions to the relevant directories as advised (755 for the directory and 644 for the files).
The images can still only be viewed in the WordPress dashboard (Media Library) when I’ve clicked through to edit image and no-where else.
My website
http://www.willbeck.com/
Any help would be appreciated.