>>zootbo+ot8
It's not trivial to display ASCII art as text in html. There's so many ways to mess it up that unless the site is dedicated to ASCII art, a simple image is really preferable.
>>ekianj+V19
You also need to preprocess the text to deal with HTML reserved characters like <
Getting an individual piece of ASCII art to work is often possible reasonably quickly, but the more examples you want to include the more odd edge cases you find.