If it's your own pics on your iPad, then the last step is the same; you need a URL to put inside the [img][/img] tags*. So the question is how to get a URL for a picture on your iPad? If you had the imgur app (or any other image uploading app), this should be relatively simply/self-explanatory. There'll be an option somewhere in the app for you to select the photo to upload, and then once you've selected it, and uploaded it, links will appear, which you can then copy and paste between the image tags.
*you can upload as an attachment, but maybe that's a little more difficult.
*you can upload as an attachment, but maybe that's a little more difficult.