I have done this but do not recall the exact file...I normally take the lazy way out.

If you can identify the image name that is currently in the place you want PayPal, you can search for it get the size and make the PayPal this size on your graphic editor.

Then name this the same name as the current one and replace it in an override folder if allowed or overwrite it and I keep a log of these so I can remember the files that were changed that could not be overriden when upgrading time rolls around.