Fastest way to transfer a bunch of photos TO iphone camera roll?

Phoneview - is a great option. It's fast too. Connect iphone, copy the files to your desired directory, disconnect. Connect other iphone, copy files to desired location on iphone. Boom!

Drag n drop ease. Free download, and cheap too. edit: it allows you to see entire disk media folder :)

You can use " PicBack - Photo Transfer App " it works with a regular USB cable, which is 3x faster than WiFi transfer and there is absolutely no third-party software to install it imports photos and videos directly To camera roll and it can also find duplicated photos , very handy and very easy to use, you can find it at the app store

"https://itun.es/i6BG5cC"

Give that a try ;)

The app GoodReader can save videos to Camera Roll. Simply transfer files to GoodReader via iTunes, then in GoodReader select "Manage Files" -> "Export" -> "Save to Photots".