As davido pointed out, there are better ways to obfuscate e-mail addresses than using images. My personal favorite is to add some normal anti-spam noise ("NOSPAM" etc.) to the address and then use CSS to hide it from normal browsers. Something like this will do the trick:

somebody@<span class=hidden>#NOSPAM#</span>example.com
[download]

where the class "hidden" is defined as:

.hidden { display: none; visibility: hidden; }
[download]

Any CSS-capable browser (and most are, these days) will hide the noise. If the user is viewing the page in a non-CSS browser, or is cutting and pasting the address, it should be obvious how to de-munge it. But a spambot probably won't even recognize it as an e-mail address. (They usually seem to look for patterns like /[-.\w]+@[-.\w]+\.$tld/, where $tld is a list of top-level domains.)

One important thing to remember is that you should not copy the example exactly. Change the name of the class, change the bogus string, add other <span> tags so the spambots can't filter out those, etc. Remember, diversity is the best defence against parasites of all kinds.