[WP] Colorize (after greyscale), depending on post type, a post image (either feat, parsed or external) and save it as new to uploads

greyscale_colorize_wp_post_images.php

<?php
// This script assumes we are in a Post Loop

// Get the image you need however you like, I use https://github.com/Jany-M/WP-Imager
$image_orig = wp_imager($img_w, $img_h, 3, '', true, '', true, null, null, true);

// Check for image headers to avoid Error 400 - if all images come always from same server/site you dont need this
$userAgent = 'Mozilla/5.0 (Windows NT 5.1; rv:31.0) Gecko/20100101 Firefox/31.0';
$ch = curl_init ($image_orig);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_USERAGENT, $userAgent);
curl_exec ($ch);
$content_type = curl_getinfo($ch, CURLINFO_CONTENT_TYPE);
//echo $content_type;
curl_close($ch);

if(!empty($image_orig) && $content_type != 'text/html; charset=us-ascii') {

    $date_img = get_the_time('Y', get_the_ID()).'/'.get_the_time('m', get_the_ID());
    $name_img = basename($image_orig);
    $strip_from_name = array(' ', '%20');
    $new_image_path = wp_upload_dir($date_img)["path"].'/colorized_'.str_replace($strip_from_name, '', $name_img);

    if(!is_file($new_image_path) || !file_exists($new_image_path)) {
        
      // Create new img
      if (exif_imagetype($image_orig) == IMAGETYPE_PNG) {
        $image = imagecreatefrompng($image_orig);
      } elseif($img_extension == 'jpg' || exif_imagetype($image_orig) == IMAGETYPE_JPEG) {
        $image = imagecreatefromjpeg($image_orig);
      } elseif($img_extension == 'gif' || exif_imagetype($image_orig) == IMAGETYPE_GIF) {
        $image = imagecreatefromgif($image_orig);
      }
    
      // First greyscale it
      imagefilter($image, IMG_FILTER_GRAYSCALE);
    
      // Colorize depending on post type
      if($post_type == 'evento') {
        imagefilter($image, IMG_FILTER_COLORIZE, 134, 117, 77);
      } elseif($post_type == 'post') {
        imagefilter($image, IMG_FILTER_COLORIZE, 72, 101, 151);
      } elseif($post_type == 'corso') {
        imagefilter($image, IMG_FILTER_COLORIZE, 201, 79, 85);
      }
    
      // If PNG keep transparency
      if (exif_imagetype($image_orig) == IMAGETYPE_PNG || exif_imagetype($image_orig) == IMAGETYPE_GIF) {
        imagealphablending($image, false);
        imagesavealpha($image, true);
      }
    
      // Save new Image
      $name_img = str_replace($strip_from_name, '', $name_img);
      if (exif_imagetype($image_orig) == IMAGETYPE_PNG) {
        imagepng($image, wp_upload_dir($date_img)["path"].'/colorized_'.$name_img);
      } elseif(exif_imagetype($image_orig) == IMAGETYPE_JPEG) {
        imagejpeg($image, wp_upload_dir($date_img)["path"].'/colorized_'.$name_img, 100);
      } elseif(exif_imagetype($image_orig) == IMAGETYPE_GIF) {
        imagegif($image, wp_upload_dir($date_img)["path"].'/colorized_'.$name_img);
      }
    
      // End Process
      imagedestroy($image);
      
    }
  
  $new_image_url = wp_upload_dir($date_img)["url"].'/colorized_'.str_replace($strip_from_name, '', $name_img);
  
  echo wp_imager($img_w, $img_h, 3, 'img-responsive', true, $new_image_url, false, null, null, null);

}

?>