diff --git a/image_test.go b/image_test.go
index dcb386459..e2ad53bcd 100644
--- a/image_test.go
+++ b/image_test.go
@@ -387,3 +387,35 @@ func TestNewImageFromSubImage(t *testing.T) {
 		}
 	}
 }
+
+type mutableRGBA struct {
+	r, g, b, a uint8
+}
+
+func (c *mutableRGBA) RGBA() (r, g, b, a uint32) {
+	return uint32(c.r) * 0x101, uint32(c.g) * 0x101, uint32(c.b) * 0x101, uint32(c.a) * 0x101
+}
+
+func TestImageFill(t *testing.T) {
+	w, h := 10, 10
+	img, err := NewImage(w, h, FilterNearest)
+	if err != nil {
+		t.Fatal(err)
+		return
+	}
+	clr := &mutableRGBA{0x80, 0x80, 0x80, 0x80}
+	if err := img.Fill(clr); err != nil {
+		t.Fatal(err)
+		return
+	}
+	clr.r = 0
+	for j := 0; j < h; j++ {
+		for i := 0; i < w; i++ {
+			got := img.At(i, j)
+			want := color.RGBA{0x80, 0x80, 0x80, 0x80}
+			if got != want {
+				t.Errorf("img At(%d, %d): got %#v; want %#v", i, j, got, want)
+			}
+		}
+	}
+}
diff --git a/imageimpl.go b/imageimpl.go
index 95575e928..c1894819a 100644
--- a/imageimpl.go
+++ b/imageimpl.go
@@ -111,8 +111,9 @@ func (i *imageImpl) Fill(clr color.Color) error {
 	if i.disposed {
 		return errors.New("ebiten: image is already disposed")
 	}
-	i.pixels.Fill(clr)
-	return i.image.Fill(clr)
+	rgba := color.RGBAModel.Convert(clr).(color.RGBA)
+	i.pixels.Fill(rgba)
+	return i.image.Fill(rgba)
 }
 
 func (i *imageImpl) clearIfVolatile() error {
@@ -125,7 +126,7 @@ func (i *imageImpl) clearIfVolatile() error {
 		return nil
 	}
 	i.pixels.Clear()
-	return i.image.Fill(color.Transparent)
+	return i.image.Fill(color.RGBA{})
 }
 
 func (i *imageImpl) DrawImage(image *Image, options *DrawImageOptions) error {
diff --git a/internal/graphics/command.go b/internal/graphics/command.go
index f6040f43b..2562cdaf4 100644
--- a/internal/graphics/command.go
+++ b/internal/graphics/command.go
@@ -136,15 +136,15 @@ func FlushCommands(context *opengl.Context) error {
 
 type fillCommand struct {
 	dst   *Image
-	color color.Color
+	color color.RGBA
 }
 
 func (c *fillCommand) Exec(context *opengl.Context, indexOffsetInBytes int) error {
 	if err := c.dst.framebuffer.setAsViewport(context); err != nil {
 		return err
 	}
-	cr, cg, cb, ca := c.color.RGBA()
-	const max = math.MaxUint16
+	cr, cg, cb, ca := c.color.R, c.color.G, c.color.B, c.color.A
+	const max = math.MaxUint8
 	r := float64(cr) / max
 	g := float64(cg) / max
 	b := float64(cb) / max
diff --git a/internal/graphics/image.go b/internal/graphics/image.go
index 50c6e194e..a285e476b 100644
--- a/internal/graphics/image.go
+++ b/internal/graphics/image.go
@@ -84,7 +84,7 @@ func (i *Image) Size() (int, int) {
 	return i.width, i.height
 }
 
-func (i *Image) Fill(clr color.Color) error {
+func (i *Image) Fill(clr color.RGBA) error {
 	// TODO: Need to clone clr value
 	c := &fillCommand{
 		dst:   i,
diff --git a/internal/pixels/pixels.go b/internal/pixels/pixels.go
index 6a1c6df2f..cb2bc5bd7 100644
--- a/internal/pixels/pixels.go
+++ b/internal/pixels/pixels.go
@@ -35,7 +35,7 @@ type drawImageHistoryItem struct {
 type Pixels struct {
 	// basePixels and baseColor are exclusive.
 	basePixels       []uint8
-	baseColor        color.Color
+	baseColor        color.RGBA
 	drawImageHistory []*drawImageHistoryItem
 	stale            bool
 }
@@ -46,19 +46,19 @@ func (p *Pixels) IsStale() bool {
 
 func (p *Pixels) MakeStale() {
 	p.basePixels = nil
-	p.baseColor = nil
+	p.baseColor = color.RGBA{}
 	p.drawImageHistory = nil
 	p.stale = true
 }
 
 func (p *Pixels) Clear() {
 	p.basePixels = nil
-	p.baseColor = nil
+	p.baseColor = color.RGBA{}
 	p.drawImageHistory = nil
 	p.stale = false
 }
 
-func (p *Pixels) Fill(clr color.Color) {
+func (p *Pixels) Fill(clr color.RGBA) {
 	p.basePixels = nil
 	p.baseColor = clr
 	p.drawImageHistory = nil
@@ -70,7 +70,7 @@ func (p *Pixels) ReplacePixels(pixels []uint8) {
 		p.basePixels = make([]uint8, len(pixels))
 	}
 	copy(p.basePixels, pixels)
-	p.baseColor = nil
+	p.baseColor = color.RGBA{}
 	p.drawImageHistory = nil
 	p.stale = false
 }
@@ -95,10 +95,10 @@ func (p *Pixels) AppendDrawImageHistory(image *graphics.Image, vertices []int16,
 //
 // Note that this must not be called until context is available.
 // This means Pixels members must match with acutal state in VRAM.
-func (p *Pixels) At(idx int, image *graphics.Image, context *opengl.Context) (color.Color, error) {
+func (p *Pixels) At(idx int, image *graphics.Image, context *opengl.Context) (color.RGBA, error) {
 	if p.basePixels == nil || p.drawImageHistory != nil || p.stale {
 		if err := p.readPixelsFromVRAM(image, context); err != nil {
-			return nil, err
+			return color.RGBA{}, err
 		}
 	}
 	r, g, b, a := p.basePixels[idx], p.basePixels[idx+1], p.basePixels[idx+2], p.basePixels[idx+3]
@@ -124,7 +124,7 @@ func (p *Pixels) readPixelsFromVRAM(image *graphics.Image, context *opengl.Conte
 	if err != nil {
 		return err
 	}
-	p.baseColor = nil
+	p.baseColor = color.RGBA{}
 	p.drawImageHistory = nil
 	p.stale = false
 	return nil
@@ -159,7 +159,7 @@ func (p *Pixels) CreateImage(context *opengl.Context, width, height int, filter
 	if err != nil {
 		return nil, err
 	}
-	if p.baseColor != nil {
+	if p.baseColor != (color.RGBA{}) {
 		if p.basePixels != nil {
 			panic("not reach")
 		}
@@ -180,7 +180,7 @@ func (p *Pixels) CreateImage(context *opengl.Context, width, height int, filter
 	if err != nil {
 		return nil, err
 	}
-	p.baseColor = nil
+	p.baseColor = color.RGBA{}
 	p.drawImageHistory = nil
 	p.stale = false
 	return gimg, nil