I am not a web developer, nor do I have any training making websites, but i am responsible for updating our company website. I am trying to add some PDF documents for our clients to read. 

I am putting the documents in rows of three with images as links but for some reasons the ones on the right hand side are a little higher than the others in the row. 

I tried using vertical align but it didn't do anything. Maybe I am trying it in the wrong spot. Can anyone take a look at the code and tell me what I am doing wrong? Aside from everything . . . 

Here is the site link:
<http://nunainnovations.com/media-literature>