Fortunately, you can zoom in at a finger's tap; not only in Safari but also into your emails in iPhone Mail and iPad Mail.
Zoom In on an Email in iPhone Mail
To enlarge part of an email text or image in iPhone Mail:
- Double-tap on the desired portion.
- Alternatively, start with two fingers close together on the portion you want to enlarge and move them apart on the screen.
To go back to full view, double-tap (twice, if necessary).
(Updated September 2012)