Facebook

Profile minimum size: 180px X 180px 
Cover photo minimum size: 400 X 150px, optimum size 820px X 312px 
Maximum file size: 4MB 
Photo formats: JPG or PNG

Google My Business

Profile minimum size: 250px X 250px 
Cover photo minimum size: 480px X 270px, optimum size 1080px X 608px 
Maximum file size: 5MB 
Photo formats: JPG or PNG