Converting Image file from one format to another

On a Windows Computer

- Open file in image editor application (MS Paint,  PhotoEditor, Picture Manager etc.) which ever application will open the file type.

-  Keep in mind that not all graphics applications can open every type of image format. so you may have to try a few if the original file format is uncommon.

- Once image is open in the application, you then want to 'save' the image in the desired alternate image format. (bmp, jpg, gif, png .etc etc).

    PhotoEditor & MS Paint : 

                        File > Save As > Save as type [file format]

    Microsoft Office Picture Manager :

                         File > Export > Export with this file format

- NOTE: you may have to tweak/modify some of the target image settings to attain a desired resolution - color depth or other attributes of the image.