Dear Employer,
I would love to help you with your task. I could totally add a page to your current website with an image gallery in form of lightbox view, and hey, I can start right now and, of course, I could have it done by today. I won't ask for the release until you're satisfied with my work, so don't worry about it :)
Please, if you have any doubt or question just ask!
Kind Regards,
Eric