Are you using the traditional Site admin webUI to administer your Webex tenant and users? If so it is a completely disconnected system and the profile picture of your users are individual managed by each user by login into your meeting url, for example company.webex.com.
If you want this to be one system, with one profile picture, you’ll need to migrate your Webex tenant from Site admin to Control Hub. Once there you can if you want use Directory Connector to synchronise your users and profile pictures from AD if that is applicable for your system landscape.