Adding your logo to Magento is probably one of the easiest procedures there are.

You will need to have your own logo, whether its a .GIF, .JPG or .PNG. We will recommend you use a .PNG as its transparency works great for the web.

All you will need to do is overwrite the current logo (if your using a .GIF image) in ‘skin/frontend/default/images/logo.gif’.

If you are however, using a .PNG image or any other format then just place it in ‘skin/frontend/default/images/‘.

Once you’ve done that go ahead into your Magento Backend, for example: ‘http://yourdomain.com/admin/‘ and go to System > Configuration. Select the ‘Design‘ tab and scroll down and select the ‘Header‘ tab. You will see something that looks like this:

Change ‘images/logo.gif‘ to ‘images/logo.png‘. Logo Alt Image represents the text that will display when you hover over the logo image. Type in your store name, this is good for Search Engines.

Hope that helped and stay tuned!

From hellothemes.com