With the magazine theme trend growing in the past year, post thumbnails have become a common feature in a lot of WordPress themes. Some of these themes use timthumb from Darren Hoyt, some other developers have developed their own way to get images from the post and display it as a thumbnail in WordPress template pages.
But with WordPress 2.9, the new feature the_post_image() will allow everyone to control and display images within posts very easily. That’s a great new feature lots of developers will be happy to hear about!