According to Google webmaster Guidelines-
Make sure that your (image) ALT attributes are
descriptive and accurate.
This new tool lets you enter a url and check how well images are following alt attribute.
Once you enter url and hit gothe tool will :
- Shows all image of the page.
- Displays the alt text associated with each image.
- A comment about how well its doing for google search.
To check your page go to Image SEO tool by feedthebot