Here’s a quick tip for changing the file extension of many types of images. Let’s say you need for a photo to be a .jpg file or but it’s a bitmap.
Many times, the quickest way to change file type on a Windows computer is to open it in using good old reliable Microsoft Paint.
Click the File tab at the top and choose Save ss from the drop-down menu. You’ll have a choice to save as .PNG, .JPG, .BMP, or .GIF. Click on other formats, to see additional options.
Click in the Save as type field for a drop-down menu of other file types.
Other photo editing programs offer this feature as well. Some programs, like Photoshop Elements offer an even greater variety of options.