In an interesting post, SP recommended not including big pictures in blog posts. Simply abandoning big pictures in your posts might not be feasible. Instead of avoiding big images altogether, a better approach might be to add various classes to your images so that you can change the style of the image later if that becomes necessary when you change the layout of your blog.
Most images have one class assigned to the image to control the float and border of the image. We use “alignleft” and “alignright” as standards in our designs. CSS allows you to assign multiple classes to a single element. In fact, you can assign as many classes to an element as you want. Each additional class helps further define the element.
Instead of abandoning large images in your blog posts for fear that a redesign might wreck your image presentation, consider adding classes to images that control size separately from their position. Instead of simply having “alignleft” on an image, the double class of “alignleft medium” could control the position of an image and the size of an image separately so that the size of the image could be altered in a subsequent blog design change through CSS while still permitting big images in a blog post.