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?
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.