So you want to allow a user to upload an image and then show them a preview of that image?
I'm not going to attempt to write the PHP for that here, but I will give you some pointers...
For the file/photo upload:
http://uk2.php.net/manual/en/functio...oaded-file.php
There's an example further down the page of how to use it.
For manipulating the image (making it smaller/bigger, creating a thumbnail, etc):
http://uk2.php.net/manual/en/functio...tefromjpeg.php
If you look down the side of that page there are LOADS of image manipulation functions. You'll probably need a few of them to do what you want. Although, if you want to leave the user's image exactly how it is (i.e. not resize it, or compress it or anything) then you could get away with not needing any of those functions. Though I wouldn't recommend leaving the image how it is (it might be huuuuge).
You can use this image function:
http://uk2.php.net/manual/en/function.imagejpeg.php
To save the image to a folder on your server, and then you can just stick
[HTML]<img src="location/where/you/saved/that/image.jpg" alt="nice pic" />[/HTML] into your page.
I hope that helps.