Tap and hold your picture in the email. Then there should appear: "Secure image" and "Copy". If you choose to secure it, it should be stored in your photo gallery.
Yes just press on it as J.A. has said, then Save Image, this is also how you save an image you find on the net.
The IPad Forum is a community of members from all walks of life and from all over the world coming together to share our experiences and to help each other learn about this wonderful piece of technology the Ipad. There is a wealth of information already here in the many threads we have so doing some searches will answer most of the questions you have. If then you cannot find the answer you are seeking then by all means post your question. There are many friendly and informed members here only too willing to help you.