class.upload.php is a powerful and mature PHP class to manage uploaded files, and manipulate images in many ways. The script is available under a GPL license.
more info about the class
<fieldset> <legend class='titrenoir'>Image upload</legend> <form name='form' enctype='multipart/form-data' method='post' action='upload_server_V5.php?upload_type=images' /> <p><input type="file" size="32" name="my_field" value="" /></p> <p class="button"><input type="hidden" name="action" value="image" /> <input type="submit" name="Submit" value="upload" /></p> </form> </fieldset>
(Translated in HTML)