Using the HTML Filters feature you can control what HTML tags will be allowed when users entering or copying text to WYSIWYG editor.
This applies to any text entered by users where HTML is allowed.
Settings of HTML Filters apply only to the front end of your site and don't apply to the admin panel. For example if "img" tag is not allowed in HTML filters, site administrator will still be able to use this tag in admin panel.
To get to this page you need to go to Admin Panel > System Configuration > HTML Filters.
On the opened page you will see the list of all HTML tags you can allow to be used or not:
After you set all desired parameters for the HTML Filters press the “Save” button at the bottom of the page to submit the settings you made.