diff --git a/image.go b/image.go
index 6110a90b9..032499f22 100644
--- a/image.go
+++ b/image.go
@@ -168,7 +168,7 @@ func (i *Image) disposeMipmaps() {
 //     * This is not a strong request since different images might share a same inner
 //       OpenGL texture in high possibility. This is not 100%, so using the same render
 //       source is safer.
-//   * All ColorM values are same
+//   * All ColorM values are same, or all the ColorM have only 'scale' operations
 //   * All CompositeMode values are same
 //   * All Filter values are same
 //