sd card reader for i pad won't work

How are the photos getting onto the card ? If you are copying them onto it yourself then you need to create a DCIM directory off the root of the card, with the photos underneath it, and the photo filenames need to be exactly 8 characters long (no spaces) plus the file extension i.e. in a similar format as if a camera had created/written them

If your cards are SDXC they won't work. SD and SDHC do but not XC. Also, the program will only see photos or videos, so if you're trying to put documents in there it won't work.