Did you need a small tool to make all that conversion of graphic files for you, so you don't have to open/save each file everytime? Then Pixy might just save your day and it's free of charge:
1. Can read .bmp, .png, .jpg, .ico, .xpm files and save them to one desired format, such as .bmp, .png, .jpg;
2. Can handle files from multiple directories in one pass;
3. Files can be renamed by adding a prefix or a suffix plus an index, in case files with identical names are found on the way;
4. Converted files can be saved in the original folders of the input files or in a separate directory;
5. Integration with the Explorer context menu for .bmp, .png and .jpg graphic files. A link called "Convert with bitnova.PiXy..." will appear when right clicking on an image;
6. The application is compliant with Windows 7 UAC installation requirements.
So all those pictures in your folders or captures from imaging devices must be converted in a specific format and it might take all day long to do that? Then let Pixy handle them and take a coffe brake. You deserve it.