You can use Settings > Privacy Settings > MMS Settings to remove attachments from either inbound or outbound messages for compliance, legal, or security reasons. Disabling MMS will prevent your messaging account from being able to send or receive multimedia attachments within messages.
Note: This setting is available to admins and org admins only. You can configure this setting for all accounts in your organization by logging in as an admin and configuring this setting on your organization account.
Configure MMS settings
To disable receiving attachments from your account's messages, use the following settings on the MMS Settings page:
Inbound MMS: Set the toggle switch to inactive (grey) to stop inbound MMS on your account and stop users from receiving pictures or other multimedia in conversations.
Outbound MMS: Set the toggle switch to inactive (grey) to stop outbound MMS on your account and stop users from sending pictures or other multimedia in conversations.
Once you disable MMS, your account won't be able to send or receive multimedia attachments within messages. If you need to re-enable MMS attachments, set the toggle switches to active (blue) for inbound or outbound MMS.