The main components of most websites are images and text. Sometimes website owners think it will be easy to create each web page in an editing program like InDesign, and then simply upload a picture of the final file. Others choose to use images of text for special effects or logos. This can give a nice aesthetic to your site but sometimes has disadvantages in areas of search engine optimization and website maintainability.
One downside of using an image of words instead of typed text is that it is bad for search engine optimization (SEO). When search provider websites, such as Google and Yahoo, decide which sites to put in their search results, they use web-crawling robots to read every website. These robots can't read the words on your site if they are actually an image and therefore can't tell what your site is about. Search engines won't put a site on their results list if they don't know what the site is about! To show you what I mean, try selecting with your cursor a single letter in the title of this blog. Now try selecting with your cursor a single letter of the Intersites logo at the top of the page; you can't do it. Even though Intersites is a word, it's on the page as an image and therefore can't be read by search engines.
Another potential disadvantage to having text as as image is that it is not easily editable for the people who maintain the website. Simple text can be changed quickly by a website administrator. Images, on the other hand, need to be designed, created, and uploaded before being put on a site.
So next time you're thinking about using an image of text consider how it might affect your site's search engine ranking and maintainability. You'll be glad you did.