nest divs for easier styling; center adorable icons

i'll leave line-by-line comments in my PR with explanations :) 
added the `.image` class instead of trying to style just the image. it's a lot easier to style divs because they're block elements, and images are inline (unless you style them otherwise). 

i also added a max-width so it wouldn't be bigger than 200px.

if you wanted to have this scale down on phones, you could do max-width with a percentage, but then you have to worry about big screens stretching your image too large. responsive images are a HUGE pain in the ass, so this isn't responsive (intentionally).