Irfanview is a teeny-tiny (used to be small enough to fit on a floppy disk; no idea if that's still the case) image viewer.

'sgot a slide-show mode with customizable settings (e.g. "do you want to see every thing in a dir, with/out subdirs? do you want a custom list of files? do you want fixed or random order? auto-progress or wait for input?), by default lets you go through the entire dir of the current image, batch rename/convert (with all SORTS of settings), lets you resize images, can (with plugins) handle audio, video, even PDFs, probably a bunch more stuff that i'm not graphically-inclined enough to know about.

oh and it's free, just like it has been for the last 20+ years.

https://www.irfanview.com/

#notsponsored