Batch Image Watermarking Script

Hi all, I need a developer to create a simple image watermarking script that will become an internal online tool for an Australian organisation. I need a web page where users can upload multiple images at once, they select a watermark from a range of set options (watermarks supplied as transparent PNGs), then the script adds the watermark and provides the user with a download link, downloading a ZIP file of all the watermarked images. It is important images don't loose any noticeable quality through this process. The script should be written in PHP, although if you prefer another language I am open to suggestions. I'd like an HTML 5 drag and drop field for the upload if it's possible (like WordPress' upload box), so please let me know how this affects the price. Also, please don't use Flash. Looking for a 5 day turnaround. Please provide me with your bid and any questions you may have! Thanks, Tom