IrfanView has been around since 1996 and is one of those programmes I have used almost every day since being one of its first fans.
It is an image viewer, editor and can play audio and video files. What makes it stand out is the size of the programme which I used to have on a floppy disk to use anywhere and the speed with which is starts up and opens a file. It was my staple programme for cropping and saving screenshots until a few weeks ago and still what I’ll use for batch editing or opening ‘difficult’ files other programmes refuse to.
Just simple and brilliant.