[url=http://java.sun.com/javase/6/docs/api/javax/imageio/ImageIO.html#read(java.net.URL)]ImageIO.read[/url]
There are versions of read that take a URL or a File.
If you *really* have to use an InputStream, you can do the following.
InputStream in = ...
BufferedImage image = ImageIO.read(ImageIO.createImageInputStream(in));