List the Template descriptions in sections author, editor, administrator

Use a Featured selection or something to do it automatically.

Use a looper of the CAT-TDx

Add a new Featured style: PORTRAIT so that the screenshot which can be very high fits completely.

Notes:

• For some galleries the size of the uploaded picture can make a difference in how the gallery looks
• You can edit the pictures in the gallery by clicking on them in the selected gallery images
• …