Justifying Text

I need to know why when I add text to a post that wordpress spreads the text out adding large spaces between words. The following text displays ok in this post and then appears spread out in posts on my site.

From:

<div align=”center”><img src=”http://www.teachingwithict.co.uk/originalimage.jpg”/></div&gt;

To:

<div align=”center”><img src=”http://www.teachingwithict.co.uk/newimage.jpg”/></div&gt;

What can I do to resolve this?