Adding Alt text to the images on your web pages will improve Google Page Rank and search engine results ranking.
Internet marketing is all about bringing visitors to your web site. One of the most important ways to increase traffic is to increase the Google Page Rank and search engine results ranking. You can pay someone else lots of money to do this, or you can make a few simple changes yourself and get the same results.
Search engines work by reading the text on your page. Most people forget about the images because they know that a computer cannot "see" an image. However, HTML provides a means for the search engine to read text that is associated with each image.

Big Red Leaf
You can see this text by moving your cursor over an image on a web page. The image of the red leaf on this page is a great example. If you are using Internet Explorer for your browser, placing the cursor over the leaf will reveal a box containing a description of the leaf. If you are using FireFox, unfortunately, you will see nothing because FireFox does not display text associated with an image in the same way that Internet Explorer does.
This text is often overlooked, or misused by web page designers. People do silly things like using the single word "logo" for the business logo. This provides no useful information and it will not help with your search engine ranking unless your business involves creating corporate logos. Even if that is your business, you can probably say something more meaningful about your services than just "logo."
To get a benefit from this method, prepare a description of each image on your web page. Write brief, specific descriptions using good grammar and complete sentences. Use your best keywords. Be organized. You need to do this for each web page, so start a document or spreadsheet. Include the name of the page, the filename, the filename of each image and the description of each image.
If you are measuring your marketing performance, you need to take some benchmark measurements before you make the changes. For each page you are going to change, record the Google Page Rank. Make a table in the document you started above. Also check your site ranking in search results for various keyword phrases. Use Google, MSN and Yahoo, at a minimum. Add as many others as you like. Record the results.
Add the description to each image. Place each description in the "src" tag for the image. Use the "alt" attribute.
<img src='file.jpg' alt='your descriptive text'>
When you are finished, save the file and upload it to your server.
Track the results by repeating your page rank and search results rank measurements at regular intervals. I suggest using the following intervals: 1 day, 3 days, 1 week, every month. You can also check more often, but keep in mind how much time it takes and if the information is worth your time.