When converting a mailing for mail client compatibility, we guarantee a height for each image. When none can be found, or in the special case of media_list, that height should however not be forced so the client can make it take the full height of the cell automatically. This is what is accomplished by this commit. X-original-commit: e80433335020a52d8f683060e98047f5ce77b054 Part-of: odoo/odoo#80621