add attachment meta, and remove pinterest pinit button from those images with meta box checked...

pinit_onlyon.php

<?php
/**
 * Plugin Name: Pinit Only On Selected Media
 * Plugin URI: http://www.rayflores.com/plugins/pinit-onlyon/ 
 * Version: 1.0
 * Author: Ray Flores
 * Author URI: http://www.rayflores.com 
 * Description: Adds ability to select media attachments to be unpinned.
 * Requires at least: 4.0
 * Tested up to: 4.1
 * screenshot of metabox: http://screencast.com/t/4o12zuTB
 * screenshot of image with no pinit button:  http://screencast.com/t/GvDre4Beh  
 */
// first lets add a meta_box to the attachment area
function attachment_fields_to_edit_pinit_only_image($form_fields, $post) {
    $checked                  = get_post_meta($post->ID, 'pinitonly', false) ? 'checked="checked"' : '';
    $form_fields['pinitonly'] = array(
        'label' => 'Remove Pin it ?',
        'input' => 'html',
        'html' => "<input type=\"checkbox\"
            name=\"attachments[{$post->ID}][pinitonly]\"
            id=\"attachments[{$post->ID}][pinitonly]\"
            value=\"1\" {$checked}/>",
        'helps' => 'Do you want the Pinit Pro button to appear on this image?'
    );
    return $form_fields;
    
}
add_filter('attachment_fields_to_edit', 'attachment_fields_to_edit_pinit_only_image', null, 2);
// then let's save it to the db 
function attachment_fields_to_save_pinit_only_image($post, $attachment){
    if (isset($attachment['pinitonly'])) {
        
        update_post_meta($post['ID'], 'pinitonly', 1);
    } else {
        update_post_meta($post['ID'], 'pinitonly', 0);
    }
    return $post;
}
add_filter('attachment_fields_to_save', 'attachment_fields_to_save_pinit_only_image', null, 2);

//add_action('wp_footer','remove_pinit_from_image',100);
add_filter('the_content', 'remove_pinit_from_image', 100);
function remove_pinit_from_image($content){
    global $pib_options, $post;
    $postID = $post->ID;
    
    
    if (is_page() || is_singular()) {
        
        
        
        $imgPattern = "/<img([^\>]*?)>/i";
        
        if (preg_match_all($imgPattern, $content, $imgTags)) {
            foreach ($imgTags[0] as $imgTag) {
                preg_match('@src="([^"]+)"@', $imgTag, $match);
                
                $image_src = $match[1];
                
                // will return /images/image.jpg
                //echo $image_src;
                $imgID = get_attachment_id_from_src($image_src);
                
                
                
                
                $img_meta = get_post_meta($imgID, 'pinitonly', true);
                
                
                if ($img_meta != 0) {
                    // you found the media items with "remove pin it option" !! 
                    
                    //Skip adding hover effect if image contains certain classes
                    $skipTheseClasses = 'pib-hover-img,pin-it-btn-custom-img,pib-nohover';
                    
                    //Add user-added CSS classes to skip hovering on
                    if (!empty($pib_options['hover_btn_ignore_classes'])) {
                        $skipTheseClasses .= ',' . $pib_options['hover_btn_ignore_classes'];
                    }
                    
                    //Convert comma delimiters to pipes for now to work with current regex
                    $skipTheseClasses = str_replace(',', '|', $skipTheseClasses);
                    
                    if (!preg_match('/' . $skipTheseClasses . '/i', $imgTag)) {
                        
                        // The ignored classes shouldn't have pib-hover-img class added to them.
                        if (!preg_match('/class=/i', $imgTag)) {
                            //image is good to go -- add the hover class
                            $pattern     = $imgPattern;
                            $replacement = '<img class="pib-nohover" $1>';
                        } else {
                            //image matches an class to skip, so don't add hover
                            $pattern     = "/<img(.*?)class=('|\")([A-Za-z0-9 \/_\.\~\:-]*?)('|\")([^\>]*?)>/i";
                            $replacement = '<img$1class=$2$3 pib-nohover$4$5>';
                        }
                        
                        $replacedImgTag = preg_replace($pattern, $replacement, $imgTag);
                        $content        = str_replace($imgTag, $replacedImgTag, $content);
                    } // end if ( ! preg_match( '/' . $skipTheseClasses . '/i', $imgTag )
                } // end if $img_meta === 1
            } // end foreach
        } // end if ( preg_match_all( $imgPattern, $content, $imgTags ))
        
        return $content;
    } // end if is_page()	
    
    
} // end function


function get_attachment_id_from_src($image_src){
    
    global $wpdb;
    $query = "SELECT ID FROM {$wpdb->posts} WHERE guid='$image_src'";
    $id    = $wpdb->get_var($query);
    return $id;
    
}