Sure!

• Go find the image you want on the internet (on your facebook, instagram, ... or any other on google)
• Right click on the image and select "copy link location" or "copy address"
• Return to your Steemit account and click on your profile picture on the top right side of screen
• From menu select "settings" and insert the copied link on "profile picture URL"
• Save and refresh the page

Hope it helps! ;)