Apple sells a $29 camera connector kit. This allows connection of the iPad either directly to an SD card or to a card reader or camera via USB. It works great. I'm planning to use my 64 GB iPad as backup. I used on over the Holidays along with Snapseed to view and email photos. Of course Snapseed works on the jpegs, but other options that use the RAW files are available. Since then Adobe has come out with an iPad version of Photoshop and the new iPad, just released last week has iPhoto.
You obviously are not an Apple fan, but the iPad is a lot more than an elegant entertainment device.