The need to change the format of the graphic file occurs, as a rule, in the case when the camera is set to record images in one of the following formats: BMP, TIFF, or RAW. They are too large and take up much space on the hard disk, memory card or other media.
If you need to change the JPEG files stored in the BMP or TIFF, you can go the easy way and use the app, which is in the computer operating system any Windows version. Open the start menu and under All programs select the program Paint.
Add in the Paint window your file. To do this, click on it with the left mouse button and while holding it down, drag the file into the program window. Now click in the upper left corner of the window, the blue button, if you hover over that appears Paint (in earlier versions of Paint you should choose section of the menu File).
Hover over the menu bar, "Save as". In recent versions of Paint submenu opens where you should choose "JPEG Image". In previous versions, the final format of the file you specify in the dialog box that appears when you activate the "Save as".
In the dialog box, select the folder in which to save the file. This can be any location on your computer's hard disk or external media (except CD-ROM drives and some mobile devices with an incompatible file system, such as iPhone/iPod/iPad). The file will be saved as a JPEG.
If the source file is saved in RAW, you should use another program to change the format. It can be as popular Photoshop and other special program (Total Image Converter, Raw Therapee, Adobe Lightroom, etc.). Download the file to one of these applications, and selecting from the File menu Save as command, specify as the final JPEG.