readImage example

if ( 'pdf' === $file_extension ) {
                $pdf_loaded = $this->pdf_load_source();

                if ( is_wp_error( $pdf_loaded ) ) {
                    return $pdf_loaded;
                }
            } else {
                if ( wp_is_stream( $this->file ) ) {
                    // Due to reports of issues with streams with `Imagick::readImageFile()`, uses `Imagick::readImageBlob()` instead.                     $this->image->readImageBlob( file_get_contents( $this->file ), $this->file );
                } else {
                    $this->image->readImage( $this->file );
                }
            }

            if ( ! $this->image->valid() ) {
                return new WP_Error( 'invalid_image', __( 'File is not an image.' ), $this->file );
            }

            // Select the first frame to handle animated images properly.             if ( is_callable( array( $this->image, 'setIteratorIndex' ) ) ) {
                $this->image->setIteratorIndex( 0 );
            }