What are Image ALT Tags and are they important?

Alt text (text that describes an image) improves accessibility for people who can’t see images on web pages, including users who use screen readers or have low-bandwidth connections.

Google uses alt text along with computer vision algorithms and the contents of the page to understand the subject matter of the image. Also, alt text in images is useful as anchor text if you decide to use an image as a link.

When choosing alt text, focus on creating useful, information-rich content that uses keywords appropriately and is in context of the content of the page. Avoid filling alt attributes with keywords (keyword stuffing) as it results in a negative user experience and may cause your site to be seen as spam.

• Bad (missing alt text): <img src="puppy.jpg" alt=""/>
• Bad (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"/>
• Better: <img src="puppy.jpg" alt="puppy"/>
• Best: <img src="puppy.jpg" alt="Dalmatian puppy playing fetch"/> 

In the above examples you can see that in the first option there is NO ALT Tag at all defined. In the second option there are too many ALT Tags (also known as Keyword Stuffing) resulting in a possible Google Penalty for the Website.
The third option is acceptable but does not say too much about the Image.The fourth Option is the best as it describes the Image perfectly.Google and other Search Engines will be able to pick up this text.

Camera Images often save Image Names as something like  5370_576.jpg in the DCIM (Digital Camera Images) Folder.An Image Name like that does not mean anything to anybody let alone the Search Engines.
Best Practice would be to rename the Image into something more descriptive and relevant as described above.

Real Estate, Property Websites often overlook this important aspect of Search Engine Optimization (SEO) as Property Sites upload many Images for each Property.
Instead of having an Image Name of 5370_576.jpg , why not rename it to second_bedroom.jpg or view_from_the_balcony_towards_mountains.jpg
Requires a bit of manual work but will be worth your while for SEO Purposes.
If you need help with renaming your Images please contact me.