Thread:Zombie pls/@comment-5739199-20150117000820/@comment-25739940-20150117004219

For the site's main background, go to the Theme Designer page, then select the Customize option on the left if it isn't already selected, then select a background color/image from there.

The little thingy you're referring to is prolly the site's favicon, to change it use the Wordmark option right under the Customize option at the Theme Designer page. The image will have to be in the .ico file format btw.