It supports BMP, JPG, PNG, WMF, EMF, and ICO image viewing. It additionally contains a converter and printer. MJZoomer is also capable of copying any image to the Windows clipboard via right-clicking on the Print button. It does not support drag n' drop or any settings to speak of. The interface is utilitarian and provides no more than what is needed to allow for straightforward image viewing and converting.
If you need to have an image viewer that is lightweight and simple to operate, then MJZoomer will provide exactly what you need.