virtuexru

This plugin will allow you to add one image or logo of your choice (defined in settings) 
to your RSS feed header. It is very simple to install/maintain and will add your website’s 
presence to your RSS feeds by giving it this personal touch.

RSS Add Image Header

This plugin will add an image/logo of your choice to all of your RSS feeds.

wooassist

Storefront Top Bar

Adds two widgets areas on top of the header of Storefront.

RSS Add Image Header vs Storefront Top Bar