Icons not showing correctly

I am a newish user of WordPress. The problem I have is the icons on the front page are not showing correctly. I had downloaded some icons when we were using the free version and tried to load them but they were showing squashed up. When we purchased the premium version I tried to use the icons that came with the theme. The same problem is happening. They are not centered in the circles…squashed and sitting down the bottom of the circle. They are 100×100.