First you need to save the pic from here to your computer by right click mouse and save as to picture folder
Then go to CAG website and click on Settings at top of page like pic below
then go to Edit Signature lick pic below
then got to part of page like picture below
Go to Option 2: Browse and get pick you saved and click upload
after it uploads you should see it on that page
click Insert Signature Picture then click Save Signature