Adding alt tags is a great way to make your site more accessible to visually impaired site visitors and allows Google search to properly identify what's going on in your site photos. This 'hidden text' is perfectly allowable so long as it's used for the purpose of describing the image, rather than keyword spamming. To create a good alt tag, you will want to be as specific as possible, keeping your alt tag description short and to the point (10-20 words).
Here's an example of alt tags.
no alt tag:
<img src="puppy.jpg" alt=""/>
Better alt tag
<img src="puppy.jpg" alt="puppy"/>
Best:
<img src="puppy.jpg" alt="Dalmatian puppy playing fetch">
To be avoided: keyword stuffing
<img src="puppy.jpg" alt="puppy dog baby
dog pup pups puppies doggies pups litter puppies dog retriever
labrador wolfhound setter pointer puppy jack russell terrier
puppies dog food cheap dogfood puppy food"/>
[youtube]3NbuDpB_BTc[/youtube]
Here's an example of alt tags.
no alt tag:
<img src="puppy.jpg" alt=""/>
Better alt tag
<img src="puppy.jpg" alt="puppy"/>
Best:
<img src="puppy.jpg" alt="Dalmatian puppy playing fetch">
To be avoided: keyword stuffing
<img src="puppy.jpg" alt="puppy dog baby
dog pup pups puppies doggies pups litter puppies dog retriever
labrador wolfhound setter pointer puppy jack russell terrier
puppies dog food cheap dogfood puppy food"/>
[youtube]3NbuDpB_BTc[/youtube]







