Computer Hope

A friend of mine has a Kodak camera. She pulled the sd card out and tried to download it to her laptop which runs Linux Ubunta. The files disappeared and she said the sd card is empty now. I don't know the file extension to search for the files. I read that Linux can't open Kodak files. What do I use to search for the files.
Thank you

If the SD card is put back into the camera, are the photos really gone, or are they just not showing on the computer? They could just be hidden. To show all files in the Home folder press CTRL+H