Image Alt Tags are an important part of SEO (search engine optimization) - proper SEO insures your website is shown in search results and can drastically improve your search engine ranking and visibility.
Ever notice how images show up in results when you search for something? Sometimes the images are perfectly relevant and sometimes they are ridiculous and have nothing to do with what you just requested. Poor search results, especially when using specific wording, is due to improper or missing SEO features. Like missing or poorly worded Alt Tags for images.
When the cutting edge tech company ThruWave from Seattle, Washington first launched their website and came to us for Search Engine Optimization, their search results under images showed a collection of shampoo, hair products and various weather and art images.