I don't know if this is of any use for anyone, but two programs I use a lot that might be handy for Simmers (For a lot of people actually, but I'm thinking Sims here)
PureRef - Allows you to float a reference image above all your other windows. I used to use it for art until I moved all my art to Procreate which has this feature built in, but I also use it for Blender - for pose referencing and for my occasional dabbling in 3d modelling
IrfanView - I'm recommending this for its Batch Conversion feature, where you can batch-edit screenshots in a crazy amount of detail. The basics are conversion of file type and resizing, but you can also batch-edit brightness, contrast, flipping, colour balance, adding watermarks and text overlay, blur, grayscale, the lot. I HIGHLY RECOMMEND only using it to batch-edit image size and file type, but if you're not fussy, the other options are there! I don't use this for Sims pics very often, I usually use it to convert my FRAPS screenshots to .png.