If you are accessing YLF from Safari on the iPad there is no way to upload a photo directly. The reason being that the iPad doesn't have a filesystem that I can access directly from the browser.
One way to do it is to use the iPhone app (you can also install the app on an iPad), but although this works it is not ideal because the app wasn't developed with the iPad in mind. As Diane says, it works at lower resolution.
And as Janet says, right now the app only shows the realtime threads. If there is demand for it we'd like to extend the app to cover all the forum categories, but first we've got to get that Android version out the door.