The size difference is noticeable but really no larger than it was in any of jones other fights. Now I think they need to take a pic of gsp/silva and people can finally put it to rest that it would be a fair fight.
This is as close as I can find for GSP vs Silva. Silva would have a size advantage especially frame wise, kind of the same as Jones vs Silva. I still think GSP has a chance though as his abilities are pretty much made to beat Silva just like Silva has a reasonable chance to beat Jones based on his skills. The way Silva has been stuffing some takedowns and destroying people lately I would probably lean towards him over either of these guys though.
And here is an interesting photo with champions at the time, too bad GSP wasn't in this picture for whatever reason. Jones looks bigger then Silva in this picture, but he also looks bigger then Velasquez too which tells you how tall and lanky Jones is, suit really makes him look filled out though.
On a side note, who else wants to see Velasquez vs Edgar and Cruz at the same time lol.