As an alternative to adding your own logo to your drupal theme, you may want to disable the stock drupal logo that appears on your templates. This can be done via a global setting in the Drupal 7 admin dashboard. Turning off the stock Drupal logo is very simple in Drupal 7 and can be done by following these instructions.
Disabling the stock Drupal logo in Drupal 7:
- Log into your Drupal 7 Admin panel.
- Using the top menu area, click on the Appearance option.
- This will bring up the themes page where it lists all themes installed within Drupal 7. Locate the Settings tab at the upper right corner of the screen and click it.
- This brings you to the main Appearance page. You will see Global Settings followed by the name of all enabled themes as a top menu bar. Be sure you are set to Global Settings by clicking on the label. You will then see a Toggle Display list. At the very top is Logo. Simply click the checkbox to disable it (be sure there is no check in the box, otherwise you have just enabled it.)
Note that not all themes support the global settings. If that is the case for your theme, simply choose the theme name at the top instead of Global Settings to go to the settings for that particular theme. Then you willl be able to turn off the logo for that theme.
- Click on the Save Configuration button at the bottom of the page to save the change. You can see how it affects your site with the below screenshots.
Before After 
