login with admin panel credentials on CometChat Admin Panel.
Click on "Settings->Editor" from the left menu.
Select "integration" from right side drop-down.
Search for below function "function getAvatar".
you have to change the path in this function. make changes as per your requirement and save it.
Note: if anything went wrong and you are not able to access CometChat. then please run below recovery URL in the browser.
yoursitename.com will be your site name.