Using a great free conversion tool
Ubuntu: Bulk image format conversion from .bmp to .jpg via command line?
If you want to convert an image from one format to another, you can use GIMP, but there is an easier way. You can use ImageMagick, which provides a way to convert images via the command line.
ImageMagick may already be installed. You can check this in the Synaptic Package Manager. Select Administration | Synaptic Package Manager from the System menu.
In the Quick Search edit box in the Synaptic Package Manager window, enter imagemagick. The search results will be displayed as you type your search term. If ImageMagick is already installed, the checkbox next to the program name will be filled in green and you can skip to the Converting an Image with ImageMagick section below.
