[Acratech]

I want to add in where the other products display in a category.
I can easily add a include to place on the page items below the items in the category, but I am not sure how to add an image in line with the items on a page. (See the attached image)
Can someone point me in the correct direction here?
I am thinking that I will have to do a includes for a file and then in the file put in something like -
{php}if ($_GET['cat'] == 20):{/php}
And if the page is category 20 it will show the image inline.