I think what that side by side picture shows is that listed heights and weights aren't extremely accurate.
Clearly there is not a huge gulf in height between the 2. I've seen Pocock's height listed at 183cm previously (it's 184 on wiki). Not sure how many adult males grow an inch or more in their mid 20s.
But anyway, what that photo shows is that Pocock is a bit bulkier and more sculpted, but there isn't a huge difference in size like many seem to believe (and try and convince others to). The biggest similarity appears to be in the legs, but it's hard to tell as Pocock is side on, hiding the width of his.