I'm using this extension on my web site and I'm absolutely happy with it. It is possible to display a gallery in an article, but also single images, standing alone or connected to a gallery. With lots and lots of parameters, you can customize it very good, but you don't need to know all of the parameters to get a good result.
The Simple Image Gallery Extended provides everything needed if you want to display images inside an article and beyond that, the developer is very active in improving it constantly, adding new features and fixing bugs.
Thank you very much for your review!