Sovereign was more combat orienteted than the Galaxy class ship so it was heavily streamlined, giving it a smaller profile and silhouette to make for a harder target. However while not as large as the Galaxy class, it was longer. You can just barely make it out in that image due to the placement of Enterprise-E sitting just ahead of the D. Galaxy came in at 641m long but Sovereign eeked in just over at 685m making it the longest ship in the fleet at the time. I say at the time because the Crossfield class (or at least the Discovery/Glenn with their extended nacelles) comes in at 740-780m long!