In reply to Tom Ripley Mountain Guide:
With the Nexus 7 that I bought for my dad, I simply connected it to my computer with a micro-usb and USB cable. From there I dragged and dropped from my computer to the Nexus 7.
After filling the Nexus with photos, music and films I've not played with it beyond that.
ES File Explorer is an excellent app that will allow you to connect to a computer network where you can copy info wirelessly from a computer to the Nexus.
And its free.
I've never seen or used the device you have in the link but I'm guessing that it is just a way of hooking up a USB card reader to a micro USB port on your Nexus.
Just use the ES File Explorer to swap the files over. It took a while to learn how to copy files as you do NOT drag and drop. The method is to select the files you want and then copy them. You then go to the folder where you want the images to go, you could even create your own folder, and then either select to paste in the folder or move into the folder. Personally I'd select to paste. That way you have images on the SD card and the Nexus.
http://to.ly/l7Lg