diff --git a/examples/edge/main.go b/examples/edge/main.go
deleted file mode 100644
index ac5ffd8a6..000000000
--- a/examples/edge/main.go
+++ /dev/null
@@ -1,115 +0,0 @@
-// 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.
-
-// +build example
-
-package main
-
-import (
-	"fmt"
-	"image/color"
-	"log"
-	"math"
-
-	"github.com/hajimehoshi/ebiten"
-	"github.com/hajimehoshi/ebiten/ebitenutil"
-)
-
-const (
-	screenWidth  = 320
-	screenHeight = 240
-)
-
-var (
-	colorImage       *ebiten.Image
-	colorImageWidth  = 64
-	colorImageHeight = 64
-	angle            = 0
-)
-
-type parts struct {
-	image *ebiten.Image
-}
-
-func (p *parts) Len() int {
-	return 1
-}
-
-func (p *parts) Src(index int) (int, int, int, int) {
-	w, h := p.image.Size()
-	return 0, 0, w, h / 2
-}
-
-func (p *parts) Dst(index int) (int, int, int, int) {
-	w, h := p.image.Size()
-	return 0, 0, w, h / 2
-}
-
-func update(screen *ebiten.Image) error {
-	if ebiten.IsKeyPressed(ebiten.KeyLeft) {
-		angle += 359
-	}
-	if ebiten.IsKeyPressed(ebiten.KeyRight) {
-		angle++
-	}
-	angle %= 360
-	if err := screen.Fill(color.White); err != nil {
-		return err
-	}
-	op := &ebiten.DrawImageOptions{}
-	op.ImageParts = &parts{colorImage}
-	op.GeoM.Translate(-float64(colorImageWidth)/2, -float64(colorImageHeight)/2)
-	op.GeoM.Rotate(float64(angle) * math.Pi / 180)
-	op.GeoM.Scale(4, 4)
-	op.GeoM.Translate(screenWidth/2, screenHeight/2)
-	if err := screen.DrawImage(colorImage, op); err != nil {
-		return err
-	}
-	if err := ebitenutil.DebugPrint(screen, fmt.Sprintf("Angle: %d [deg]", angle)); err != nil {
-		return err
-	}
-	return nil
-}
-
-func main() {
-	var err error
-	colorImage, err = ebiten.NewImage(colorImageWidth, colorImageHeight, ebiten.FilterNearest)
-	if err != nil {
-		log.Fatal(err)
-	}
-	pixels := make([]uint8, 4*colorImageWidth*colorImageHeight)
-	for j := 0; j < colorImageHeight; j++ {
-		for i := 0; i < colorImageWidth; i++ {
-			idx := 4 * (i + j*colorImageWidth)
-			switch {
-			case j < colorImageHeight/2:
-				pixels[idx] = 0xff
-				pixels[idx+1] = 0
-				pixels[idx+2] = 0
-				pixels[idx+3] = 0xff
-			default:
-				pixels[idx] = 0
-				pixels[idx+1] = 0xff
-				pixels[idx+2] = 0
-				pixels[idx+3] = 0xff
-			}
-		}
-	}
-	if err := colorImage.ReplacePixels(pixels); err != nil {
-		log.Fatal(err)
-	}
-	if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Edge (Ebiten Demo)"); err != nil {
-		log.Fatal(err)
-	}
-}
diff --git a/image_test.go b/image_test.go
index e6e700ba1..6c95e5c5d 100644
--- a/image_test.go
+++ b/image_test.go
@@ -563,3 +563,87 @@ func TestImageSize(t *testing.T) {
 		}
 	}
 }
+
+type halfImagePart struct {
+	image *Image
+}
+
+func (p *halfImagePart) Len() int {
+	return 1
+}
+
+func (p *halfImagePart) Src(index int) (int, int, int, int) {
+	w, h := p.image.Size()
+	return 0, 0, w, h / 2
+}
+
+func (p *halfImagePart) Dst(index int) (int, int, int, int) {
+	w, h := p.image.Size()
+	return 0, 0, w, h / 2
+}
+
+// Issue 317
+func TestImageEdge(t *testing.T) {
+	const (
+		img0Width  = 16
+		img0Height = 16
+		img1Width  = 32
+		img1Height = 32
+	)
+	img0, err := NewImage(img0Width, img0Height, FilterNearest)
+	if err != nil {
+		t.Fatal(err)
+	}
+	pixels := make([]uint8, 4*img0Width*img0Height)
+	for j := 0; j < img0Height; j++ {
+		for i := 0; i < img0Width; i++ {
+			idx := 4 * (i + j*img0Width)
+			switch {
+			case j < img0Height/2:
+				pixels[idx] = 0xff
+				pixels[idx+1] = 0
+				pixels[idx+2] = 0
+				pixels[idx+3] = 0xff
+			default:
+				pixels[idx] = 0
+				pixels[idx+1] = 0xff
+				pixels[idx+2] = 0
+				pixels[idx+3] = 0xff
+			}
+		}
+	}
+	if err := img0.ReplacePixels(pixels); err != nil {
+		t.Fatal(err)
+	}
+	img1, err := NewImage(img1Width, img1Height, FilterNearest)
+	if err != nil {
+		t.Fatal(err)
+	}
+	red := color.RGBA{0xff, 0, 0, 0xff}
+	transparent := color.RGBA{0, 0, 0, 0}
+	for a := 0; a < 360; a++ {
+		if err := img1.Clear(); err != nil {
+			t.Fatal(err)
+		}
+		op := &DrawImageOptions{}
+		op.ImageParts = &halfImagePart{img0}
+		op.GeoM.Translate(-float64(img0Width)/2, -float64(img0Height)/2)
+		op.GeoM.Rotate(float64(a) * math.Pi / 180)
+		op.GeoM.Translate(img1Width/2, img1Height/2)
+		if err := img1.DrawImage(img0, op); err != nil {
+			t.Fatal(err)
+		}
+		for j := 0; j < img1Height; j++ {
+			for i := 0; i < img1Width; i++ {
+				c := img1.At(i, j)
+				if c == red {
+					continue
+				}
+				if c == transparent {
+					continue
+				}
+				t.Errorf("img1.At(%d, %d) want: red or transparent, got: %v", i, j, c)
+			}
+		}
+	}
+}