Profile photo
Square works best. Surfaces in Google rich results and every byline. If the head sits off-center, use “Adjust position” to reframe — the circle is what readers see.
Photos
Profile photo and cover.
The two images that paint the top of your public page. Both save the moment you upload — no separate Save button.
Cover image
The wide banner above your masthead. 16:5 landscape works best; leave it blank and your profile shows a clean paper-warm gradient.