Using Angular markup like {{hash}} in a srcset attribute doesn't
work right: The browser will fetch from the URL with the literal
text {{hash}} until Angular replaces the expression inside
{{hash}}. The ngSrcset directive solves this problem.
The buggy way to write it:
<img srcset="http://www.gravatar.com/avatar/{{hash}} 2x" alt="Description"/>
The correct way to write it:
<img ng-srcset="http://www.gravatar.com/avatar/{{hash}} 2x" alt="Description" />
<IMG
  ng-srcset="template">
...
</IMG>
      | Param | Type | Details | 
|---|---|---|
| ngSrcset | template | 
         any string which can contain   |