Don't know if it's been mentioned yet but Format Factory is excellent for converting videos/pics as well as reducing the size of video files with very little if any reduction in picture quality.
For example I had a number of classic porn movies DL'ed that were over 1GB in size, converted them to MP4 with Format Factory and the size was reduced by half and practically no loss in quality.
https://formatfactory.en.uptodown.com/windows