In the inventory you can go to settings to take a fully zoomed out screenshot. However, it doesn't make a screenshot or save them anywhere after taking a screenshot. The folder ~/.local/share/StardewValley/Screenshots does not exist. There is no screenshots folder anywhere on my computer.

I fixed it with help of the Stardew Valley discord:

This is how to solve the problem:

1. In the Finder, select Home from the Go menu (your user folder will open up).

2. Do command + shift + . to show all hidden folders.

3. Add a folder named .local in your user folder.

4. Add a folder named share in .local.

5. Add a folder named StardewValley in share.

6. Add a folder named Screenshots in StardewValley.

7. Take a screenshot in Stardew Valley, it should appear here.