diff --git a/src/EventSubscriber/StageFileProxySubscriber.php b/src/EventSubscriber/StageFileProxySubscriber.php
index e0285d6de429772354bb803015e880b96ab2c27b..7f0b7a3710253269975359ae312fefce62d8cfba 100644
--- a/src/EventSubscriber/StageFileProxySubscriber.php
+++ b/src/EventSubscriber/StageFileProxySubscriber.php
@@ -155,11 +155,18 @@ class StageFileProxySubscriber implements EventSubscriberInterface {
     // If file is fetched and use_imagecache_root is set, original is used.
     $paths = [$relative_path];
 
-    // Webp support.
-    $is_webp = FALSE;
-    if (strpos($relative_path, '.webp')) {
-      $paths[] = str_replace('.webp', '', $relative_path);
-      $is_webp = TRUE;
+    // Image style file conversion support.
+    $unconverted_path = static::getFilePathWithoutConvertedExtension($relative_path);
+    if ($unconverted_path !== $relative_path) {
+      if ($config->get('use_imagecache_root')) {
+        // Check the unconverted file path first in order to use the local
+        // original image.
+        array_unshift($paths, $unconverted_path);
+      }
+      else {
+        // Check the unconverted path after the image derivative.
+        $paths[] = $unconverted_path;
+      }
     }
 
     foreach ($paths as $relative_path) {
@@ -175,12 +182,12 @@ class StageFileProxySubscriber implements EventSubscriberInterface {
       // Is this imagecache? Request the root file and let imagecache resize.
       // We check this first so locally added files have precedence.
       $original_path = $this->manager->styleOriginalPath($relative_path, TRUE);
-      if ($original_path && !$is_webp) {
+      if ($original_path) {
         if (file_exists($original_path)) {
           // Imagecache can generate it without our help.
           return;
         }
-        if ($config->get('use_imagecache_root')) {
+        if ($config->get('use_imagecache_root') && $unconverted_path === $relative_path) {
           // Config says: Fetch the original.
           $fetch_path = StreamWrapperManager::getTarget($original_path);
         }