Casio's ".cam" file extension is created by Casio digital cameras whenever a picture is taken using a Casio digital camera. This file must be opened by the Casio photo software instead of any other kind of photo viewing software, such as "Windows Picture and Fax Viewer." Converting the ".cam" file extension to the universal ".jpeg" extension allows it to be opened by many different kinds of photo viewing software, not just Casio's.
Locate the folder on your computer where the ".cam" files are.
Click on the "Tools" tab on the upper-right corner of the window and open the "Folder Options..."
Access the "View" tab and click on the box next to "Hide extensions for known file types" to remove the check in the box.
Click the "Apply" button and then click the "OK" button to close the window and save the changes.
Right-click the ".cam" file and click on the "Rename" option. By typing, replace the ".cam" file extension with the ".jpeg" extension.
click "Yes." in the window that pops up warning you that changing the file extension can change the way the file is used.