If you’re posting to a blog which updates your front page automatically, it’s vital to incorporate images. Without them you’re finely crafted site will just look like a wall of text. The image should be related and doesn’t have to anything special just represent the subject.
So if you’re writing a post on how to access a Japanese proxy for example – a simple Japanese flag would be sufficient. The image is relevant and instantly defines the subject. If you’re interested in this subject – people use these Japanese servers in order to access web sites which restrict access based on location. For example many Japanese online banking systems only work when you are physically in Japan in order to increase security. Of course this is fine if a Russian hacker is trying to access your account but a bit of a nuisance if you’re a businessman from Tokyo who wants to pay his mobile phone bill!