One of the great things about the iPhone is that it's easy to attach a photo to an email to quickly share something you've snapped with friends and family.
However, it's not so obvious how to attach more than one image. When browsing through your Camera Roll with full-screen photos, the sharing button (bottom left) is fairly prominent; tap it and Email Photo is the first option.
To attach multiple photos (up to five are allowed per email) you need to return to the thumbnail view in the Camera Roll and tap the sharing button at the top right of the screen.
This switches to the Select Items view and you can tap several photos to select them. A green tick appears on each photo you tap.
Tap Share at the bottom of the screen, then Email. The photos will be inserted in the body of a new email.
When you've added the recipients, a subject and a message (the latter two are optional), tap Send. A message will appear asking which size to send the photos: Small, Medium, Large or Actual Size. Next to each option you'll see the total size of the email in KB or MB. It's unwise to send more than 10MB in one go - some email systems will reject the message entirely if it's too large.