Digital cameras forum: Unable to view photos written to SD card?

I just purchased a SanDisk 5-in-1 Card Reader/Writer and am attempting to write photos to a SanDisk 128MB card. I am able to view the photos on the card while in the reader/writer, but not when I put it in either of my cameras (the camera screens say 'no images"). I have also tried to write photos from my p.c. to a Sony memory stick to use in my Sony 50" LCD television without success. The images on both media are viewable while in the reader/writer. I have a Dell 8200, 250GB & 80 GB HD, 1 GB memory and am using Windows Explorer to write to memory cards. I have formatted both memory media and have used the SD card in both of my cameras without problems. The instructions included with the reader/writer are very minimal and I may be using the wrong procedure for writing to the cards? The images are being transferred to the cards, but possibly in the wrong format for the cameras/t.v.? Obviously, I am trying to write to these cards to use the SD card in a digital frame and the Memory Stick in the slot on my Sony LCD T.V.

Any help greatly appreciated!