diff --git a/internal/restorable/image.go b/internal/restorable/image.go
index e5e0ae764..d91b6569f 100644
--- a/internal/restorable/image.go
+++ b/internal/restorable/image.go
@@ -89,10 +89,18 @@ func newImageWithoutInit(width, height int, volatile bool) *Image {
 // The returned image is cleared.
 func NewImage(width, height int, volatile bool) *Image {
 	i := newImageWithoutInit(width, height, volatile)
-	i.ReplacePixels(nil, 0, 0, width, height)
+	i.Clear(0, 0, width, height)
 	return i
 }
 
+func (i *Image) Clear(x, y, width, height int) {
+	w, h := dummyImage.Size()
+	geom := (*affine.GeoM)(nil).Scale(float64(width)/float64(w), float64(height)/float64(h))
+	geom = geom.Translate(float64(x), float64(y))
+	colorm := (*affine.ColorM)(nil).Scale(0, 0, 0, 0)
+	i.DrawImage(dummyImage, 0, 0, w, h, geom, colorm, opengl.CompositeModeCopy, graphics.FilterNearest)
+}
+
 // NewScreenFramebufferImage creates a special image that framebuffer is one for the screen.
 //
 // The returned image is cleared.
@@ -104,7 +112,7 @@ func NewScreenFramebufferImage(width, height int) *Image {
 	}
 	theImages.add(i)
 	runtime.SetFinalizer(i, (*Image).Dispose)
-	i.ReplacePixels(nil, 0, 0, width, height)
+	i.Clear(0, 0, width, height)
 	return i
 }
 
@@ -131,8 +139,6 @@ func (i *Image) makeStale() {
 }
 
 // ReplacePixels replaces the image pixels with the given pixels slice.
-//
-// If pixels is nil, ReplacePixels clears the specified reagion.
 func (i *Image) ReplacePixels(pixels []byte, x, y, width, height int) {
 	w, h := i.image.Size()
 	if width <= 0 || height <= 0 {
@@ -146,16 +152,7 @@ func (i *Image) ReplacePixels(pixels []byte, x, y, width, height int) {
 	// For this purpuse, images should remember which part of that is used for DrawImage.
 	theImages.makeStaleIfDependingOn(i)
 
-	if pixels != nil {
-		i.image.ReplacePixels(pixels, x, y, width, height)
-	} else {
-		w, h := dummyImage.Size()
-		geom := (*affine.GeoM)(nil).Scale(float64(width)/float64(w), float64(height)/float64(h))
-		geom = geom.Translate(float64(x), float64(y))
-		colorm := (*affine.ColorM)(nil).Scale(0, 0, 0, 0)
-		vs := vertices(w, h, 0, 0, w, h, geom)
-		i.image.DrawImage(dummyImage.image, vs, colorm, opengl.CompositeModeCopy, graphics.FilterNearest)
-	}
+	i.image.ReplacePixels(pixels, x, y, width, height)
 
 	if x == 0 && y == 0 && width == w && height == h {
 		if i.basePixels == nil {
@@ -175,17 +172,9 @@ func (i *Image) ReplacePixels(pixels []byte, x, y, width, height int) {
 		return
 	}
 	idx := 4 * (y*w + x)
-	if pixels != nil {
-		for j := 0; j < height; j++ {
-			copy(i.basePixels[idx:idx+4*width], pixels[4*j*width:4*(j+1)*width])
-			idx += 4 * w
-		}
-	} else {
-		zeros := make([]byte, 4*width)
-		for j := 0; j < height; j++ {
-			copy(i.basePixels[idx:idx+4*width], zeros)
-			idx += 4 * w
-		}
+	for j := 0; j < height; j++ {
+		copy(i.basePixels[idx:idx+4*width], pixels[4*j*width:4*(j+1)*width])
+		idx += 4 * w
 	}
 	i.stale = false
 }
diff --git a/internal/restorable/images_test.go b/internal/restorable/images_test.go
index d74eaf3a8..60bf4e1d6 100644
--- a/internal/restorable/images_test.go
+++ b/internal/restorable/images_test.go
@@ -569,69 +569,4 @@ func TestDoubleResolve(t *testing.T) {
 	}
 }
 
-func TestClear(t *testing.T) {
-	pix := make([]uint8, 4*4*4)
-	for i := range pix {
-		pix[i] = 0xff
-	}
-
-	img := NewImage(4, 4, false)
-	img.ReplacePixels(pix, 0, 0, 4, 4)
-	// This doesn't make the image stale. Its base pixels are available.
-	img.ReplacePixels(nil, 1, 1, 2, 2)
-
-	cases := []struct {
-		Index int
-		Want  color.RGBA
-	}{
-		{
-			Index: 0,
-			Want:  color.RGBA{0xff, 0xff, 0xff, 0xff},
-		},
-		{
-			Index: 3,
-			Want:  color.RGBA{0xff, 0xff, 0xff, 0xff},
-		},
-		{
-			Index: 4,
-			Want:  color.RGBA{0xff, 0xff, 0xff, 0xff},
-		},
-		{
-			Index: 5,
-			Want:  color.RGBA{0, 0, 0, 0},
-		},
-		{
-			Index: 7,
-			Want:  color.RGBA{0xff, 0xff, 0xff, 0xff},
-		},
-		{
-			Index: 8,
-			Want:  color.RGBA{0xff, 0xff, 0xff, 0xff},
-		},
-		{
-			Index: 10,
-			Want:  color.RGBA{0, 0, 0, 0},
-		},
-		{
-			Index: 11,
-			Want:  color.RGBA{0xff, 0xff, 0xff, 0xff},
-		},
-		{
-			Index: 12,
-			Want:  color.RGBA{0xff, 0xff, 0xff, 0xff},
-		},
-		{
-			Index: 15,
-			Want:  color.RGBA{0xff, 0xff, 0xff, 0xff},
-		},
-	}
-	for _, c := range cases {
-		got := byteSliceToColor(img.BasePixelsForTesting(), c.Index)
-		want := c.Want
-		if got != want {
-			t.Errorf("base pixel [%d]: got %v, want %v", c.Index, got, want)
-		}
-	}
-}
-
 // TODO: How about volatile/screen images?
diff --git a/internal/shareable/shareable.go b/internal/shareable/shareable.go
index 864b3c787..2392600be 100644
--- a/internal/shareable/shareable.go
+++ b/internal/shareable/shareable.go
@@ -189,8 +189,7 @@ func (i *Image) dispose() {
 	i.backend.page.Free(i.node)
 	if !i.backend.page.IsEmpty() {
 		// As this part can be reused, this should be cleared explicitly.
-		x0, y0, x1, y1 := i.region()
-		i.backend.restorable.ReplacePixels(nil, x0, y0, x1, y1)
+		i.backend.restorable.Clear(i.region())
 		return
 	}