Download and install any software to view pictures. If you are not able to quickly find a program, don't worry. Open the start menu, then Programs – accessories. There is a simple image editor Paint. To change the format of the picture you can also. Any of these programs, open the image, the format of which you want to change.
Go to the menu "File" select "Save as...". In the resulting window, type line of the file specify the desired format.
The most common picture formats – BMP, JPG, PNG, GIF. Each of them has its own characteristics. For example, the BMP format often does not use compression, and therefore preserved in this picture takes up more disk space. JPG by tweaking its filters allows to reduce several times the size of the final file, but may degrade image quality. The GIF format allows you to create animated image consisting of successive fixed pictures. The PNG format was created to replace GIF format and is widely used on the Internet due to the so-called "lossless compression".
If you allow the functionality of the program, the type of format you will see a button "Advanced/Settings". Clicking on it, you can change the default filter values for the selected format at its discretion.
Print the name of the new file or leave it still and click OK. The image format changed.