'No Image' message when try to open photos

Can anyone help with message of ‘No image’ coming up on San Disk 4GB memory card. I transferred two folders containing the jpegs, then removed the yellow folders, thinking this might be blocking the pictures from being read.  I then copied pictures over to memory card, but when put back in the camera, NO IMAGE shows up with no other options! HELP! This is for a Christmas present!

 Also you put a powerpoint presentation on the memory card?

the camera should create a folder named DCIM or something similar. for the camera to see the pictures (assuming they are in a format the camera is compatible with) the pictures would have to be in that folder.