The PHPBuilder.com site has a quick new tutorial showing how to upload images to your server via a PHP script (including some error checking).
One of the most frequently asked questions about PHP is "how can I use PHP to upload an image". In this article we'll discuss the details of how you can do just that!
Their script is done in three steps - an HTML form to accept the input, the PHP script to handle the upload (working with the $_FILES superglobal) and another HTML page to let the user know their upload was a success. When the file is uploaded, they check for a few things: the internal error PHP could throw, ensuring that the uploaded file exists and checking to ensure that the file is an image. Only then is it moved over to the true uploads directory to be stored.