To restore the image to the original size, click the Home Button, or to view the Image in full screen click on the Full Screen Button.
The iPhone SeaDragon app works on iPhone and iPod Touch and OS 2.1 or higher.
Here’s how well SeaDragon lets your zoom
Try SeaDragon’s Zoom In this Image below
To test SeaDragon’s capability you can head to their site : SeaDragon, and try out some sample images or just enter the URL to an image on the web and to see the zoom capable image generated that you could embed on your blog/site or share it on the social media.