Photo size for individual posts and front page

Still trying to figure out my slider size issue, but this is a different issue. My photos are coming out a little too big on the front page and on the actual blog post. To test I just took a photo from the pinboard them page (the coffee). When I use it it comes out bigger on my front page and individual post than their’s even though the photo is the same size. Reducing the photo to less than the original size when inserting into a post makes it too small. Not sure what I’m missing here.

http://brownchicchronicles.com/