I just spent 3 very frustrating hours trying to figure out why the digital picture frame I bought my mom a couple of years ago wouldn't show the images I send her. It is a NuVue 561 and works fine with the 2 GB SD card from her camera, but not the 2 GB SD card I bought for her.
I finally figured out that the NuVue only supports 1.0/1.1 of the SD specification, but the new cards are all 2.0 of the specification. The problem I was having is the 2.0 GB card I bought for her camera two Christmas' ago is a 1.1 (so it worked), but anything new is 2.0.
I eventually found that the Kingston Memory 2.0 GB cards are 1.0/1.1 so that works in the NuVue.
Overview of what we're doing: I bought my mom a card reader for her Mac laptop to copy images from CD/camera to the card in the picture frame. This way I can send her CDs of the kids, she picks what pictures she wants and can update the frame.