I wish I knew. I've never used an ipad. Apple designed the system to be very restricted and closed, limiting what the user can do. I've heard that even Flash isn't allowed on ipad, and flash is about as common a web technology as you can get. I suspect in time Apple will come under increased pressure to be more open with their devices and make them work better on the web.
In the meantime, you can post a photo to an online photo storage site and then embed it here using the [img] tag, like this:
[img]http://remotehost.com/image.jpg[/img ]
(You'd remove the space from the closing tag there.)