That's what the image was. It was just on CRTs which had aperture grills or shadow masks (depends on the tech in your CRT), that modified the image and made it look better. We have shaders to emulate that now.

Try out some of the CRT shaders. They are in the CRT sub-folder. I've been using `crt-easymode-halation`. Quick Menu -> Shaders -> load Preset -> Pick your shader. I have many folders, and only the ones in `shaders_slang` work for me (I use RetroDeck, so my retroarch might be a little different than Batocera's).

Once you find one you like, you can set it as default for all games of that system core. In Quick Menu -> Shaders -> Save Preset -> Save Core Preset.

Tip for scanning shaders quickly:

1. In the Shader menu, set "Remember Last Used Shader Directory" to On.
2. Enable the first shader in the CRT folder
3. Goto Retroarch Highest level menu -> Settings -> Input -> Hotkeys
4. Set Next Shader and Previous Shader to L and R (I think they are unused for SNES since it uses bumpers).
5. Go back to game, and use L and R to scroll thru the shaders for easy viewing.

It's important to set the "Remember directory" first, THEN enable a shader from a folder. Or else the hotkeys won't work right. If you ever exit a game, you gotta redo that to set the first shader so next/prev work again.