We've been properly labelling and tagging our images for years. Some of our websites get most of their visitors from Google Images.
Google Images is the greatest SEO reserve left in the world. Chris Silver Smith of Netconcepts let the cat out of the bag in 2006 and told the whole world about optimising for Google images. But it's hard work optimising images for Google Images and most webmasters still can't be bothered. There's still gold - or at least visitors - in those hills.
As Chris didn't cover the technical details in-depth, here's a step by step guide for optimising your images for Google images.
Most websites publish their images like this:
<img src="https://foliovision.com/images/192a/986943.jpg" alt="image">
Where's the problem? Missing height and width, meaningless directory name, meaningless file name, generic alt tag.
Here's what a properly formatted image should look like: