Quite a nice personal touch for a PWA instance is to add the company logo as the background image. This is very simple to do for both 2010 and 2013, 2013 is even easier than 2010.
Firstly we will look at 2010, the quickest way to add an image to the PWA homepage is to use CSS, an example is below:
Update the image URL to the correct image, save the CSS in notepad or preferred editor, for this example I called the file backimage.inc. Then upload the file to PWA, in this example it was uploaded to the Shared Documents library. Edit the PWA homepage and add a content editor web part, then link to the backimage.inc file:
Apply the change and click OK, then save the page and you will see your image set as the background:
For 2013 you just click Change the Look from the settings cog, click current:
Click Change and browse to the image and add. Click Try it out, if you are happy with the image, click Yes keep it:
This will add the image to all pages in 2013. 
