Is there a way we can set Alt Tags for images automatically in a Drupal site

As a general rule, I typically don't argue other Experts' solutions, but I have to add this one since I feel it's important.

jQuery is an interesting solution, but with jQuery used that way, none of the search engines will pick up the ALT tags, (business goal) and neither will screen readers and assistive devices (WCAG/accessibility guidelines).  This is because they don't parse or execute JavaScript or jQuery. The way that code is written, though, will work for adding the TITLE attribute, but not the ALT attribute. So the tooltip would work when hovering over the image for a user using a regular browser. Of course, adding one more line of jQuery could add the ALT as well, but you'd still be in the same position.

The other thing I see is that all images would have the page/node name as the title attribute. ALT and TITLE tags are supposed to be descriptive of the image itself, not the page/node. It helps with both of the above goals, business and universal access:

Refs:
http://support.google.com/webmasters/bin/answer.py?hl=en&answer=114016
http://www.w3.org/TR/2012/NOTE-WCAG20-TECHS-20120103/H37.html

HagayMandel is right, however, in that without doing preprocessing it's difficult to obtain the goal. However, there is a theme function for it that you can override in your theme. You just need to change the values inside the $attributes array in the function to output all themed images with ALT, TITLE, or any other attribute (Drupal 7, but there is a link there for Drupal 6):

http://api.drupal.org/api/drupal/includes%21theme.inc/function/theme_image/7

Basically, you'd copy the theme_image() code into your template.php file, rename it to match your theme (see below) and add a little code to modify how alt tags are set. Voilà! All of your alt tags should be set (be sure to clear the Drupal cache before testing):

function techpedia_image($variables) {
  $attributes = $variables['attributes'];
  $attributes['src'] = file_create_url($variables['path']);

  foreach (array('width', 'height', 'alt', 'title') as $key) {

    if (isset($variables[$key])) {
      $attributes[$key] = $variables[$key];
    }
  }

  // NEW code to set alt tags that aren't already set (not verified to be correct):
  if (!isset($attributes['alt'])) {
    // do something here to set the alt tag
  }

  return '<img' . drupal_attributes($attributes) . ' />';
}

Select all Open in new window

Cheers,

Mike