XnConvert allows you to convert your photos from one format to the other in an intuitive and accessible way.
More than 500 formats are supported by the program, including most popular ones like JPG and PNG as well as TIFF, GIF and GIF.
You can apply several masks before you convert your images. These include watermarks and signatures as well as special effects. You can apply them to one image or to large numbers of images at once.
If you are looking for an image convertor, XnConvert can be a good choice. It has a simple interface that allows you to change the format of favorite photos.