Sticker widget

Sticker puts one image of your choosing on the desktop and stays out of the way: it never captures the mouse, so clicks pass straight through to whatever is underneath. Transparent PNGs sit directly on the wallpaper, which is what makes it feel like a sticker rather than a frame.

Pick any local png, jpeg, webp or gif in the widget settings and choose how it fills the tile: contain shows the whole image with transparent margins, cover fills the tile and crops. The image is never stretched. The widget needs no permissions; only the one file you pick is ever read.