It seems that the two pics show two different views of (nearly) the same moment in time...but...the top pic shows a banner behind the signing party that is not in the bottom pic. Interesting.
It’s a trick of perspective. The low angle shot from the front hides the banner behind their torsos.
The lower pic has several MA State legislators standing behind Romney/Kennedy/whomever; the top photo is just the few. Don’t know if they would conceal the banner.
Hard to imagine you could get quite the same facial expressions from the men at the same time.