I think that you can click on Reply and then add a picture by clicking on the second button above the place where you are writing your message. You can add "Image" by clicking there. Or you can add a Video by clicking the third button and then following the instructions to tell it where to find your image or video file. probably you have it saved to your desk top? I just did a trial of a Beach Picture which I think is going to be rather large, but it should give you and me the idea for doing it right next time. Sigh ....
Hope this helps.
Hmmmmm. I don't know how to attach photo via my i-phone. Should be the same, but not sure how to find the file.
Your Photograph image is viewable when clicking on the "image.jpg"