My favourite picture viewer IrfanView thankfully gives you the option to add your own icons. I made this set in the full range of sizes, 16x16, 24x24, 32x32, 48x48, 56x56 and 64x64. If you use IrfanView and crave these icons, download the whole set here or go to Irfan's skin page and scroll down to my set. I made these with the amazing Affinity Designer.