diff --git a/image.go b/image.go
index 6a4790de2..faffe5d9e 100644
--- a/image.go
+++ b/image.go
@@ -269,7 +269,7 @@ func NewImageFromImage(source image.Image, filter Filter) (*Image, error) {
 	size := source.Bounds().Size()
 	w, h := size.X, size.Y
 	checkSize(w, h)
-	rgbaImg := graphics.CopyImage(source)
+	rgbaImg := restorable.CopyImage(source)
 	r := restorable.NewImageFromImage(rgbaImg, w, h, glFilter(filter))
 	i := &Image{r}
 	runtime.SetFinalizer(i, (*Image).Dispose)
diff --git a/internal/graphics/image.go b/internal/graphics/image.go
index 16d8bbcfe..e2b8caeb6 100644
--- a/internal/graphics/image.go
+++ b/internal/graphics/image.go
@@ -16,60 +16,12 @@ package graphics
 
 import (
 	"image"
-	"image/color"
-	"image/draw"
-	"runtime"
 
 	"github.com/hajimehoshi/ebiten/internal/affine"
 	"github.com/hajimehoshi/ebiten/internal/math"
 	"github.com/hajimehoshi/ebiten/internal/opengl"
 )
 
-func CopyImage(origImg image.Image) *image.RGBA {
-	size := origImg.Bounds().Size()
-	w, h := size.X, size.Y
-	newImg := image.NewRGBA(image.Rect(0, 0, math.NextPowerOf2Int(w), math.NextPowerOf2Int(h)))
-	switch origImg := origImg.(type) {
-	case *image.Paletted:
-		b := origImg.Bounds()
-		x0 := b.Min.X
-		y0 := b.Min.Y
-		x1 := b.Max.X
-		y1 := b.Max.Y
-		palette := make([]uint8, len(origImg.Palette)*4)
-		for i, c := range origImg.Palette {
-			rgba := color.RGBAModel.Convert(c).(color.RGBA)
-			palette[4*i] = rgba.R
-			palette[4*i+1] = rgba.G
-			palette[4*i+2] = rgba.B
-			palette[4*i+3] = rgba.A
-		}
-		index0 := 0
-		index1 := 0
-		d0 := origImg.Stride - (x1 - x0)
-		d1 := newImg.Stride - (x1-x0)*4
-		pix0 := origImg.Pix
-		pix1 := newImg.Pix
-		for j := 0; j < y1-y0; j++ {
-			for i := 0; i < x1-x0; i++ {
-				p := int(pix0[index0])
-				pix1[index1] = palette[4*p]
-				pix1[index1+1] = palette[4*p+1]
-				pix1[index1+2] = palette[4*p+2]
-				pix1[index1+3] = palette[4*p+3]
-				index0++
-				index1 += 4
-			}
-			index0 += d0
-			index1 += d1
-		}
-	default:
-		draw.Draw(newImg, image.Rect(0, 0, w, h), origImg, origImg.Bounds().Min, draw.Src)
-	}
-	runtime.Gosched()
-	return newImg
-}
-
 type Image struct {
 	texture     *texture
 	framebuffer *framebuffer
diff --git a/internal/restorable/copy.go b/internal/restorable/copy.go
new file mode 100644
index 000000000..2d6271be6
--- /dev/null
+++ b/internal/restorable/copy.go
@@ -0,0 +1,69 @@
+// Copyright 2017 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package restorable
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+	"runtime"
+
+	"github.com/hajimehoshi/ebiten/internal/math"
+)
+
+func CopyImage(origImg image.Image) *image.RGBA {
+	size := origImg.Bounds().Size()
+	w, h := size.X, size.Y
+	newImg := image.NewRGBA(image.Rect(0, 0, math.NextPowerOf2Int(w), math.NextPowerOf2Int(h)))
+	switch origImg := origImg.(type) {
+	case *image.Paletted:
+		b := origImg.Bounds()
+		x0 := b.Min.X
+		y0 := b.Min.Y
+		x1 := b.Max.X
+		y1 := b.Max.Y
+		palette := make([]uint8, len(origImg.Palette)*4)
+		for i, c := range origImg.Palette {
+			rgba := color.RGBAModel.Convert(c).(color.RGBA)
+			palette[4*i] = rgba.R
+			palette[4*i+1] = rgba.G
+			palette[4*i+2] = rgba.B
+			palette[4*i+3] = rgba.A
+		}
+		index0 := 0
+		index1 := 0
+		d0 := origImg.Stride - (x1 - x0)
+		d1 := newImg.Stride - (x1-x0)*4
+		pix0 := origImg.Pix
+		pix1 := newImg.Pix
+		for j := 0; j < y1-y0; j++ {
+			for i := 0; i < x1-x0; i++ {
+				p := int(pix0[index0])
+				pix1[index1] = palette[4*p]
+				pix1[index1+1] = palette[4*p+1]
+				pix1[index1+2] = palette[4*p+2]
+				pix1[index1+3] = palette[4*p+3]
+				index0++
+				index1 += 4
+			}
+			index0 += d0
+			index1 += d1
+		}
+	default:
+		draw.Draw(newImg, image.Rect(0, 0, w, h), origImg, origImg.Bounds().Min, draw.Src)
+	}
+	runtime.Gosched()
+	return newImg
+}
diff --git a/internal/graphics/image_test.go b/internal/restorable/copy_test.go
similarity index 97%
rename from internal/graphics/image_test.go
rename to internal/restorable/copy_test.go
index c48f5c1f8..d011e22aa 100644
--- a/internal/graphics/image_test.go
+++ b/internal/restorable/copy_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package graphics_test
+package restorable_test
 
 import (
 	"image"
@@ -20,7 +20,7 @@ import (
 	"image/color/palette"
 	"testing"
 
-	. "github.com/hajimehoshi/ebiten/internal/graphics"
+	. "github.com/hajimehoshi/ebiten/internal/restorable"
 )
 
 func TestCopyImage(t *testing.T) {