diff --git a/.gitmodules b/.gitmodules
index e6c99e0..f8ba08e 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,6 +1,6 @@
 [submodule "vendor/github.com/pkg/errors"]
 	path = vendor/github.com/pkg/errors
 	url = https://github.com/pkg/errors
-[submodule "vendor/golang.org/x"]
-	path = vendor/golang.org/x
-	url = https://golang.org/x
+[submodule "vendor/golang.org/x/image"]
+	path = vendor/golang.org/x/image
+	url = https://golang.org/x/image
\ No newline at end of file
diff --git a/process.go b/process.go
index de6df52..0f0181a 100644
--- a/process.go
+++ b/process.go
@@ -78,7 +78,7 @@ func (p *Processor) Resize(img *image.NRGBA) (image.Image, error) {
 		pw := c.Width - int(float64(c.Width)-(float64(p.NewWidth)/100*float64(c.Width)))
 		ph := c.Height - int(float64(c.Height)-(float64(p.NewHeight)/100*float64(c.Height)))
 		if pw > newWidth || ph > newHeight {
-			err := errors.New("the generated image size should be less than original image size.")
+			err := errors.New("The generated image size should be less than original image size.")
 			return nil, err
 		}
 		// Reduce image size horizontally
diff --git a/vendor/golang.org/x/crypto b/vendor/golang.org/x/crypto
deleted file mode 160000
index faadfbd..0000000
--- a/vendor/golang.org/x/crypto
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit faadfbdc035307d901e69eea569f5dda451a3ee3
diff --git a/vendor/golang.org/x/net b/vendor/golang.org/x/net
deleted file mode 160000
index 054b33e..0000000
--- a/vendor/golang.org/x/net
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 054b33e6527139ad5b1ec2f6232c3b175bd9a30c
diff --git a/vendor/golang.org/x/sys b/vendor/golang.org/x/sys
deleted file mode 160000
index 062cd7e..0000000
--- a/vendor/golang.org/x/sys
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 062cd7e4e68206d8bab9b18396626e855c992658
diff --git a/vendor/golang.org/x/text b/vendor/golang.org/x/text
deleted file mode 160000
index d69c40b..0000000
--- a/vendor/golang.org/x/text
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit d69c40b4be55797923cec7457fac7a244d91a9b6
diff --git a/vendor/golang.org/x/tools b/vendor/golang.org/x/tools
deleted file mode 160000
index 6648760..0000000
--- a/vendor/golang.org/x/tools
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 66487607e2081c7c2af2281c62c14ee000d5024b