Wordpress Bootstrap 3 responsive images

function.php

<?php 
//----------------------------------------------------------/
//  responsive images [ 1) add img-responsive class 2) remove dimensions ]
//----------------------------------------------------------/

function bootstrap_responsive_images( $html ){
  $classes = 'img-responsive'; // separated by spaces, e.g. 'img image-link'

  // check if there are already classes assigned to the anchor
  if ( preg_match('/<img.*? class="/', $html) ) {
    $html = preg_replace('/(<img.*? class=".*?)(".*?\/>)/', '$1 ' . $classes . ' $2', $html);
  } else {
    $html = preg_replace('/(<img.*?)(\/>)/', '$1 class="' . $classes . '" $2', $html);
  }
  // remove dimensions from images,, does not need it!
  $html = preg_replace( '/(width|height)=\"\d*\"\s/', "", $html );
  return $html;
}
add_filter( 'the_content','bootstrap_responsive_images',10 );
add_filter( 'post_thumbnail_html', 'bootstrap_responsive_images', 10 );

Beautiful!

SUper et vraiment gentil

Thanks! Very helpful!

Thanks for this !, It worked perfect!

This worked for me. But with one slight adjustment to make sure the photoswipe.min.js did no produce a JS error, this lines were commented out:

      `$html = preg_replace( '/(width|height)=\"\d*\"\s/', "", $html );`

Alternative version used as shown here, with some tweaks as required:
woocommerce/woocommerce#15376