You can download old IrfanView versions from these sites:
Oldapps.com or Oldversion.com
There were numerous changes, here are only the more important things.
Version 4.51 ( - CURRENT VERSION - )
(Release date: 2018-02-27)
- Improved JPG save option: "Set file size" (no RIOT PlugIn needed)
- New options in IrfanView Shell Extension (PlugIns website)
- Support for animated WebP files
- Some fixes (Zoom box text, EXE/DLL icon loading)
- Several PlugIns are changed/updated, please install the newest versions:
http://www.irfanview.com/plugins.htm
[
Older versions - History]
