I transferred many photos from my Samsung galaxy S3 to myNexus10 gallery section and I want to delete many of them but I don't know how. Any suggestions, thanks
The easiest way is to open the gallery and long press a pic you want to delete. Then select other pics, and tap the delete (garbage can on top right). Or open each pic, hit the menu button (3 dots) and select delete.
OR mount to a computer, navigate to the pic folder(s) on the device and delete the file for each pic.