While the photo is being displayed, if you touch the 'curly arrow' icon at the top right hand side of the screen there are a range of options presented, one of which is to email the photograph.
Thanks Tim.
Is there a way to attach a photo to an existing email. In other words if I get an email from someone and want to reply to it attaching a photo that is on my iPad, can I do that?
Yes. You just copy the photo and paste into the email if you want. Go to your photos, touch a photo and get the copy prompt, tap, then switch to your email and paste.