.jpg is a file extension designating JPEG which is a certain image compression. If you have any image editing software, you can save it as .jpg. Just go to Save As and somewhere there will be an option for .jpg, .tif, ect. Most digital cameras will automatically take pictures with the JPEG compression, you would have to alter your settings in order to take TIFF or RAW.
I hope that helps a little for your question, Annik. If I were you, I would just check around to see if you have a way to open images on your computer and save them, if you can, then you ought to be able to save that image as a .jpg file.