diff --git a/image.go b/image.go
index 19e9f7d4e..ab5df2a68 100644
--- a/image.go
+++ b/image.go
@@ -400,7 +400,7 @@ type DrawTrianglesShaderOptions struct {
 	Uniforms map[string]interface{}
 
 	// Images is a set of the source images.
-	// All the images must be the same sizes.
+	// All the images' sizes must be the same.
 	Images [4]*Image
 
 	// FillRule indicates the rule how an overlapped region is rendered.
@@ -542,7 +542,7 @@ type DrawRectShaderOptions struct {
 	Uniforms map[string]interface{}
 
 	// Images is a set of the source images.
-	// All the images must be the same sizes.
+	// All the images' sizes must be the same.
 	Images [4]*Image
 }