Ticket #38522: 38522.diff

src/wp-includes/class-wp-image-editor-imagick.php

@@ -147 +147 @@
                 try {
                         $this->image = new Imagick();
                         $file_parts = pathinfo( $this->file );
+                        $filename = $this->file;
 
                         // By default, PDFs are rendered in a very low resolution.
                         // We want the thumbnail to be readable, so increase the rendering dpi.
                         if ( 'pdf' == strtolower( $file_parts['extension'] ) ) {
                                 $this->image->setResolution( 128, 128 );
+
+                                // Only load the first page.
+                                $filename .= '[0]';
                         }
 
                         // Reading image after Imagick instantiation because `setResolution`
                         // only applies correctly before the image is read.
-                        $this->image->readImage( $this->file );
+                        $this->image->readImage( $filename );
 
                         if ( ! $this->image->valid() )
                                 return new WP_Error( 'invalid_image', __('File is not an image.'), $this->file);