Trouble with header logo

Hi everyone,

https://www.vcestudyguides.com

As you can see, there’s a white border around my logo which I don’t want. The image itself has been made transparent, so I’m not too sure why I’m still getting white colour around the logo.

Secondly, the logo on the page is smaller than its original size, so if anyone has any ideas why, please share this with me.

I’d appreciate it if you could tell me what to code as well, since I’m not too great in the coding department ??

Regards!