Why I can not find some css with grep? I'm newbie and I don't know how Drupal 7 work!
I want to remove with and height from below code:

&lt;img typeof="foaf:Image" src="http://ashkanplastic.loc/sites/default/files/styles/large/public/slider-1a_0.jpg?itok=k4X3QU5U" width="480" height="236" alt=""&gt;


Could you please introduce to me why I can not find 480 with $ grep -H -R 492?
And please help to remove width and height.
Please check Remove width and height from img tag in Drupal output (for certain content type) for removing width and height from image.

You will never find width and height with grep command because width and height are added by drupal theme function.

Check https://api.drupal.org/api/drupal/modules%21image%21image.module/function/theme_image_style/7 and  https://api.drupal.org/api/drupal/includes%21theme.inc/function/theme_image/7 for more details.