They seem solid to me - my advice is that you set up a macro (if you're using photoshop) to Trim (Image > Trim...) transparent pixels, and then set the canvas size to the icon size. This will centre your sprite for you.
Tsunami Bomb - The Simple Truth
We could run away
Leave behind anything paper
Not knowing where we're going to stay
When there's no Mondays
You're part of me, it's so easy to see the simple truth
When I'm in your arms, I feel safe from harm and sorrow too
You're part of me, it's so easy to see the simple truth
But most of all, nothing couldn't be solved when I'm with you
