how to set one of my pictures as screensaver

System Preferences > Desktop & Screen Saver > Screen Saver > choose one of the modes that uses a picture > Screen Saver Options > Choose Folder...

Done with reference to Mavericks OS.

Clearly this will work best when you have more than one image.

I presume you meant Screen Saver and not Desktop background (same preference group)?

We keep on saying folder and we mean folder not a single image.

As already stated, a static image is not a saving your screen. The idea behind a screen saver is there is no static image on the display. The placement of the image is constantly changing and does not burn into a single location causing excessive wear on the elements in that location.

You want to chose "Classic" and the folder with only one picture as the source. You should be aware that having the same unchanging image on the screen for very long can cause image persistence.

Avoiding image persistence on Apple displays - Apple Support

I've heard that somewhere. 😎

"it" referred to the folder, not the picture.

You could create a folder with just the one picture you want to show and select it.

Choose a folder of pictures even if there is only one picture in the folder.

You need to create a folder, put the picture you want to use in that folder, then use "Choose folder" and select that folder.

dialabrain wrote:

I've heard that somewhere. 😎

Yes, I know. It was in my original post. If I say folder I mean folder. 😉 > Choose Folder...

Did you click on the link I posted? It explains image persistence and how to avoid it.

you're very welcome.