Same pixel dimensions but different sizes?

I am trying to understand why sometimes I get different output from what seems like the same pixel dimensions. Here I show two pictures of menus  from Adobe Encore edited in Photoshop. One was the default menu that I choose that said it was a “WIDE” version and the other was a standard size (not WIDE). I got confused, because when edited in Photoshop they both said 720 px X 480 px. I burned a DVD that the video was rendered for NTSC DV Wide (Adobe Media Encoder), and when I played it, the menu it had pillar boxing and letter boxing. I understand that when this happens means the video is the wrong size. So I went back to Photoshop and noticed that the videos say the same pixel dimensions, however they also have a Image Size amount listed. For the not WIDE version it reads 854.3K  for the WIDE version it reads 1012.5K. I also noticed there is now way to change this. What is going on here? How can you know that your video is the correct size for your desired output type. Thanks