Converting for use on iPad Kindle app

So I've come across this issue, bear with me, it's my first attempt using the iPad's Kindle app.

If I use the official 'send to Kindle' pc software (because I am trying to simplify the process of converting to Kindle), it'll convert fine, except the cover is a thumbnail with a white border. I've attached an example of a unedited kindle book vs a .doc conversion.

Attached Thumbnails