Tribute page: problem with caption

Hi there!

I changed my tribute page to use bootstrap, but I have a problem with my image’s caption.
First of all, both image’s captions have different spacing. Does someone know, why?
In addition, I would like to have smaller captions, meaning less white space and the text centered (and maybe a smaller font size). I don’t know how to get the caption more flat and the text centered vertically.

Can you help me solve this?