Set the profile property Avatar ($avatar) to a url resource of a gif, jpg, jpeg, or png to update the picture in a profile.
The value of the Avatar ($avatar) profile property must be an image URL that ends in .gif, .png, .jpeg, or .jpg. Mixpanel detects the property value by filetype and not MIME type. So Mixpanel cannot access an image from a URL that does not end in in .gif, .png, .jpeg, or .jpg.
If a profile does not include the Avatar ($avatar) property, then Mixpanel looks for a Gravatar account associated with the email address stored in the $email property.
If a profile displays a picture from Gravatar, there is no way to remove it.
If there is no Avatar ($avatar) property and the email address set on the Email ($email) property is not associated with a Gravatar account, then a profile will not display a picture.