SageThumbs uses a right click to convert the format of a photo. You can preview it, set it as a wallpaper or convert the format. There is also a separate menu to select the pixels, size and file type for the image.
This extension can give you options to convert the image by just a right click on Windows. You don't have to open it. It is always available and no need to run a software. Most of all it is free!
This is an open source shell extension that makes converting and using images on Windows platform easier.
This is very easy and convenient to use with a great time cutting opportunity with lots of formats which makes sending or attaching to different documents simpler.
It works only on Windows platforms: XP/2003/Vista/2008/7/2012/8/8.1 32/64-bit
You also need at least 5 MB of disk space.
It is free!