diff --git a/wp-admin/includes/image.php b/wp-admin/includes/image.php
index 5f7b583d5d..4ae53b9c3a 100644
--- a/wp-admin/includes/image.php
+++ b/wp-admin/includes/image.php
@@ -221,14 +221,28 @@ function wp_generate_attachment_metadata( $attachment_id, $file ) {
 		$fallback_sizes = apply_filters( 'fallback_intermediate_image_sizes', $fallback_sizes, $metadata );
 
 		$sizes = array();
+		$_wp_additional_image_sizes = wp_get_additional_image_sizes();
 
 		foreach ( $fallback_sizes as $s ) {
-			$sizes[ $s ]['width']  = get_option( "{$s}_size_w" );
-			$sizes[ $s ]['height'] = get_option( "{$s}_size_h" );
+			if ( isset( $_wp_additional_image_sizes[ $s ]['width'] ) ) {
+				$sizes[ $s ]['width'] = intval( $_wp_additional_image_sizes[ $s ]['width'] );
+			} else {
+				$sizes[ $s ]['width'] = get_option( "{$s}_size_w" );
+			}
 
-			// Force thumbnails to be soft crops.
-			if ( ! 'thumbnail' === $s ) {
-				$sizes[ $s ]['crop'] = get_option( "{$s}_crop" );
+			if ( isset( $_wp_additional_image_sizes[ $s ]['height'] ) ) {
+				$sizes[ $s ]['height'] = intval( $_wp_additional_image_sizes[ $s ]['height'] );
+			} else {
+				$sizes[ $s ]['height'] = get_option( "{$s}_size_h" );
+			}
+
+			if ( isset( $_wp_additional_image_sizes[ $s ]['crop'] ) ) {
+				$sizes[ $s ]['crop'] = $_wp_additional_image_sizes[ $s ]['crop'];
+			} else {
+				// Force thumbnails to be soft crops.
+				if ( ! 'thumbnail' === $s ) {
+					$sizes[ $s ]['crop'] = get_option( "{$s}_crop" );
+				}
 			}
 		}
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 988da4434b..0859fe830a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-39616';
+$wp_version = '4.8-alpha-39617';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.