In WordPress Dashboard go to the Appearance submenu and click on Customize.
After clicking on customize you will in theme Customizer.
Here you have to click on Page Template than About Page
In About Content Here you can Team,Funfact, Skill, CTA. of Hide/Show.
Go to Customize -> Page Template ->About Page
You have to use Skill Section Image Size 717Px X 486Px
You have to use Skill Section Image Size 217Px X 426Px