how to change .cr2 photo files to jpegs..havelinuxhacker messing with my files...

I have some obsessed hacker who knows linux inside and out messing with my computer files...the minute I download pictures from camera of myself ( I am an actress) there all over them taking some for them selves and trying to control them and throwing up the ugly ones to try to mentally abuse me...now the last time I downloaded pictures the scum took 40 of them for them selves and then wouldn't allow them to be jpegs only .cr2 files...I need to know how to change them into jpegs on my computer.....I know it is possible...please let me know...they waisted like 2 hours messing with me as I proceed with the jpeg and then before I knew it they turned it into a .cr photo file on me and blurred the photo out so I couldn't use it at all....