Thank you for sharing the website! I am sure, I am going to use it big time :-)
I am a little surprised to know that you are adding pictures in your old posts!! Do your old posts also get lot of visits?
How big is your blog? Approx. monthly visits that you get? I noticed that you have been maintaining the blog since June 2010.... That's a long period! You must have learned a lot through the journey!!!
My old posts get almost all my traffic, I started late 2010 and wrote almost all of my posts in 2011/2012 and a few in 2013 and then pretty much nothing for the past two years. I was working at a super stressful job with insane hours and just didn't feel compelled to write. I have done basic upkeep. I was still earning a bit of ad revenue and selling some copies of my books (despite no marketing at all) but it is 3 maybe 4 out of my 100 posts which get 95% of my traffic. So those are the areas I will be focusing on for new digital products/e-books and possibly some coaching or courses.
When I started writing, longer posts with texts were okay, but it seems like over all the shift is to shorter, snappier posts for the time crunched (especially in my field) so I do think it is worth adding pictures. I don't remember the stats either but it is something in the hundreds of times as far as being more effective. As I go through them I am updating, making sure all the links work, seeing how I can recycle update and consolidate the work I have done into new formats I'm at 132 posts. At the very least all of my old posts that I am keeping will have a headline picture, a new headline and be more broken up shorter paragraphs lists whenever possible, more white space.
My total hits is 630250 which is about 10500 a month on average. It has fallen dramatically since my all time high of posting regularly which was 28500 a month. Right now it is about 12,000. So my goal is to get it up to at least where it was in 2013.
The thing to realize is it takes a LONG time to get started. Most of your hits come from old posts what have targeted keywords people are looking for in search results, it takes a while to build up enough momentum to be noticeable. Many people fail because they quite to soon before they have that critical mass. It took me 20 MONTHS of sitting around 4-5000 then suddenly I hit that critical mass and the next month jumped up to 19,000 and was steadily climbing, so it does take time.
I highly recommend checking out Jon Morrow's work
http://boostblogtraffic.com/ I have learned the most useful things from him - that dude knows his field.