Though digital pictures come in a variety of file formats, most of the pictures on your computer probably use the common JPEG format. Most digital cameras save pictures in the JPEG format to maintain good visual quality without creating large files. In addition, many programs can only open pictures that are saved in the JPEG format.
If you have a picture stored in another file format, such as TIFF or bitmap, you can make a copy of it in JPEG format. It's also possible to save a copy of a JPEG picture in a different format. When you save a copy of a picture in a different format, the original picture is not replaced.
Open Windows Photo Gallery by clicking the Start button , clicking All Programs, and then clicking Windows Photo Gallery.
Click the picture you want to change.
On the toolbar, click Open, and then click Paint.
Paint will open with your picture displayed.
Click the File menu in Paint, and then click Save As.
Click the Save as type list, and then click the file type you want to use to convert your picture.
If you want to protect a JPEG picture from additional loss of visual quality, you can save it as a TIFF, which, unlike a JPEG, does not lose small amounts of visual quality every time it is edited and saved.
Paint does not work with all file formats. For example, you cannot open a picture in RAW format by using Paint. For file types that Paint does not support, you should use a photo editing program.