I fought with this particular Wordpress template from Organic Themes for quite a while. I like everything else about the template, but the masthead logo is limited to a square 120x120 pixel block. Almost all of my own logos, and client logos are rectangular. To solve this problem, login to your Wordpress installation, and go to Appearance > Editor. Select Stylesheet.css to edit.
- Find the #header #logo section, and then change the width value to something other than 16%. I chose 85% for mine. The site title and the logo will now overlap
- Change the #header .site-title font-size to 0em (basically non-existent)
- Click update.
That is a quick and dirty way to get the logo to work in something other than a square.