If there aren't many complaining then there's probably not much reason to do anything about it. I wasn't sure if I was the only one bothered by it. It may be because I am new and easily distracted while scrolling through, I tend to focus on pictures and dates to get an idea of progress, it's when I see somebody else's picture post I get confused unless I've made special note of who is who.
The only solution I can think of, without deterring others from sharing their progress along side others grows would be to ask that people put their picture posts in drop down / hidden menus, if you installed the appropriate VB Plugin to do that, or just post a link instead.
As far as what we do to control off-topic posts on our site, our members tend to point it out to the offending poster, which usually keeps the forum tidy. The problem is, we have an Off-Topic section and the "attitude" tends to leak into other areas of the site, it's more or less attitude control. Unfortunately (or fortunately) the nature of this entire site is laid back, so controlling posting style I can assume from section to section may be difficult.
The more I think about it the sharing of posts and pictures is more indicative of of the lifestyle of the average user here, which is cool, though personally I would prefer my own grow log or art thread not be drowned out by others posting pictures in it. Perhaps a poll would be in order to get a sense of the overall opinion here.
That said, really love the site and enjoy it very much, it's a wealth of information and from one owner to another I can appreciate the work put into it.