diff --git a/image.go b/image.go
index 776f58e58..8a8be65d1 100644
--- a/image.go
+++ b/image.go
@@ -367,7 +367,6 @@ func (i *Image) DrawTrianglesWithShader(vertices []Vertex, indices []uint16, sha
 	mode := driver.CompositeMode(options.CompositeMode)
 
 	us := []interface{}{}
-	var firstImage *Image
 	for _, v := range options.Uniforms {
 		switch v := v.(type) {
 		case *Image:
@@ -375,17 +374,6 @@ func (i *Image) DrawTrianglesWithShader(vertices []Vertex, indices []uint16, sha
 				panic("ebiten: the given image to DrawTriangles must not be disposed")
 			}
 			us = append(us, v.buffered)
-			if firstImage == nil {
-				firstImage = v
-			} else {
-				b := v.Bounds()
-				us = append(us, []float32{
-					float32(b.Min.X),
-					float32(b.Min.Y),
-					float32(b.Max.X),
-					float32(b.Max.Y),
-				})
-			}
 		default:
 			us = append(us, v)
 		}
@@ -395,25 +383,17 @@ func (i *Image) DrawTrianglesWithShader(vertices []Vertex, indices []uint16, sha
 	// The actual value is set at graphicscommand package.
 	us = append([]interface{}{[]float32{0, 0}}, us...)
 
-	var bx0, by0, bx1, by1 float32
-	if firstImage != nil {
-		b := firstImage.Bounds()
-		bx0 = float32(b.Min.X)
-		by0 = float32(b.Min.Y)
-		bx1 = float32(b.Max.X)
-		by1 = float32(b.Max.Y)
-	}
-
 	vs := make([]float32, len(vertices)*graphics.VertexFloatNum)
 	for i, v := range vertices {
 		vs[i*graphics.VertexFloatNum] = v.DstX
 		vs[i*graphics.VertexFloatNum+1] = v.DstY
 		vs[i*graphics.VertexFloatNum+2] = v.SrcX
 		vs[i*graphics.VertexFloatNum+3] = v.SrcY
-		vs[i*graphics.VertexFloatNum+4] = bx0
-		vs[i*graphics.VertexFloatNum+5] = by0
-		vs[i*graphics.VertexFloatNum+6] = bx1
-		vs[i*graphics.VertexFloatNum+7] = by1
+		// TODO: Remove these values for the source region.
+		vs[i*graphics.VertexFloatNum+4] = 0
+		vs[i*graphics.VertexFloatNum+5] = 0
+		vs[i*graphics.VertexFloatNum+6] = 0
+		vs[i*graphics.VertexFloatNum+7] = 0
 		vs[i*graphics.VertexFloatNum+8] = v.ColorR
 		vs[i*graphics.VertexFloatNum+9] = v.ColorG
 		vs[i*graphics.VertexFloatNum+10] = v.ColorB
diff --git a/internal/graphicscommand/command.go b/internal/graphicscommand/command.go
index 86ddf98d7..cf3b49f75 100644
--- a/internal/graphicscommand/command.go
+++ b/internal/graphicscommand/command.go
@@ -410,28 +410,10 @@ func (c *drawTrianglesCommand) Exec(indexOffset int) error {
 	if c.shader != nil {
 		us := make([]interface{}, len(c.uniforms))
 
-		firstImage := true
 		for i := 0; i < len(c.uniforms); i++ {
 			switch v := c.uniforms[i].(type) {
 			case *Image:
 				us[i] = v.image.ID()
-				if firstImage {
-					firstImage = false
-					continue
-				}
-
-				// Convert pixels to texels.
-				w, h := v.InternalSize()
-				i++
-				region := c.uniforms[i].([]float32)
-				vs := []float32{
-					region[0] / float32(w),
-					region[1] / float32(h),
-					region[2] / float32(w),
-					region[3] / float32(h),
-				}
-
-				us[i] = vs
 			default:
 				us[i] = v
 			}
diff --git a/internal/restorable/shader_test.go b/internal/restorable/shader_test.go
index a7194abd6..362c963dd 100644
--- a/internal/restorable/shader_test.go
+++ b/internal/restorable/shader_test.go
@@ -116,9 +116,7 @@ func TestShaderMultipleSources(t *testing.T) {
 		[]float32{0, 0},
 		srcs[0],
 		srcs[1],
-		[]float32{0, 0, 1, 1},
 		srcs[2],
-		[]float32{0, 0, 1, 1},
 	}
 	dst.DrawTriangles(nil, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), nil, driver.CompositeModeCopy, driver.FilterNearest, driver.AddressUnsafe, s, us)
 
diff --git a/internal/shareable/image.go b/internal/shareable/image.go
index 2aa7b9f7a..e27b2665f 100644
--- a/internal/shareable/image.go
+++ b/internal/shareable/image.go
@@ -357,23 +357,11 @@ func (i *Image) DrawTriangles(img *Image, vertices []float32, indices []uint16,
 		s = shader.shader
 	}
 
-	firstImage := true
 	us := make([]interface{}, len(uniforms))
 	for i := 0; i < len(uniforms); i++ {
 		switch v := uniforms[i].(type) {
 		case *Image:
 			us[i] = v.backend.restorable
-			if !firstImage {
-				i++
-				region := uniforms[i].([]float32)
-				us[i] = []float32{
-					region[0] + oxf,
-					region[1] + oyf,
-					region[2] + oxf,
-					region[3] + oyf,
-				}
-			}
-			firstImage = false
 		default:
 			us[i] = v
 		}
diff --git a/internal/testing/shader.go b/internal/testing/shader.go
index 32c5b82c9..200bbca8b 100644
--- a/internal/testing/shader.go
+++ b/internal/testing/shader.go
@@ -288,10 +288,8 @@ func ShaderProgramFill(r, g, b, a byte) shaderir.Program {
 //
 // Uniform variables's indices and their values are:
 //
-//   0:    the framebuffer size (Vec2)
-//   1:    the first images (Texture2D)
-//   2n:   the n-th image (Texture2D)
-//   2n+1: the n-th image's region (Vec4)
+//   0:  the framebuffer size (Vec2)
+//   1-: the images (Texture2D)
 //
 // The first image's size and region are represented in attribute variables.
 //
@@ -363,7 +361,7 @@ func ShaderProgramImages(imageNum int) shaderir.Program {
 							},
 							{
 								Type:  shaderir.UniformVariable,
-								Index: 2 * i,
+								Index: i + 1,
 							},
 							texPos,
 						},