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Update: Thanks for pointing me in the right direction. I starting searching on Google for pointers on enabling the Authorship markup. Came across this really helpful video - http://youtu.be/YyIQzHD8rBY Followed those steps - in linking my personal Google+ profile and enabling the Bio section with myself as Author in the blog posts. And so far looking good. Tested a post with the Rich Snippets Testing Tool in Google Webmaster - and it's picking up the Authorship with the photo quite nicely! Thanks for the help YyIQzHD8rBY

You'll absolutely want to get the blog moved to the subdirectory. Tell your developers they must use 301 redirects to point the traffic from the old subdomain pages to the new location. As long as the blog's site structure and URLs remain the same, that will be a pretty straightforward redirect to write. Once they've done the redirect, test by going to a bunch of the old page addresses and making sure you end on the new pages. Also use a header-checking tool on the new pages to confirm that it's actually showing that 301 redirect was used (not a 302, for example) The sooner you do this the better, so that new incoming links will be pointing directly to the new location instead of being redirectd through the old location. if you want best bang for the buck, check for the strongest links that currently point to the old site and see if you can get their webmasters to update them to point to the new URLs. Even pages that are redirected don't pass 100% of their authority through the 301 to the new page, and there is evidence to indicate that the 301s pass less authority as they age. All good reasons to get the move done as soon as practical. Good luck! Paul P.S. If your blog has a name that people may begin to recognize & remember  (ie that is different from the site name) strongly consider naming the folder /the-blog-name instead of just /blog. Every bit of distinctiveness helps!