Where can I find a printable keyboard layout when the option key is pressed?

I am new to Apple, and I am new to use a Swiss French keyboard; unfortunately, a lot of useful characters are only available when the option key is pressed.

I would like to have an image of them available to be printed or to be quickly available, so that I can learn them. I have noticed that you can see the layout from Sys preferences > Keyboard > Input Sources > press the option key, but the image is too small and to be honest I do not know how to take a screenshot while pressing the option key.

Do you have any suggestion or good image?

Solution 1:

Use Keyboard Viewer to see the keyboard instead of sys preferences.

Use the Grab app or the Screenshot app in Applications/Utilities to take a picture of it.