I loaded my pictures onto my computer from my T2i and when I put the card back into the camera the images were gone. I'm not sure where they went as I am very new to DSLR world?
You most likely moved your pictures from the SD card onto your computer's hard drive rather than making a copy of them. Therefore, the image files are most likely alive and well somewhere on the computer's hard drive.
I have them on my computer, but they are not on the memory card anymore. Once I put the card back in the camera it said no images? I didn't erase them so I thought if I put the card back in the camera they would be there. I'm very confused.
You could copy (not move) the images from the computer's hard drive back to the SD card in the DCIM/100CANON folder. Then you'd have one copy of each image on the computer hard drive, and another one in the original folder on the SD card where the images were originally recorded by the camera.
After that, you will be able to put the SD card back in the camera and see your photos on the LCD monitor of the camera.
Comments
After that, you will be able to put the SD card back in the camera and see your photos on the LCD monitor of the camera.
See the guide on pages 168-169:
http://gdlp01.c-wss.com/gds/0/0300004720/01/eosrt3i-eos600d-im-en.pdf
Also, you might want to read page 71 for instructions for playing back your images on the camera.