diff --git a/internal/graphicscommand/command.go b/internal/graphicscommand/command.go
index 8dd54b1ed..ca0395a1a 100644
--- a/internal/graphicscommand/command.go
+++ b/internal/graphicscommand/command.go
@@ -424,7 +424,16 @@ func (c *drawTrianglesCommand) Exec(indexOffset int) error {
 	}
 
 	if c.shader != nil {
-		return theGraphicsDriver.DrawShader(c.dst.image.ID(), c.shader.shader.ID(), c.nindices, indexOffset, c.mode, c.uniforms)
+		us := map[int]interface{}{}
+		for k, v := range c.uniforms {
+			switch v := v.(type) {
+			case *Image:
+				us[k] = v.image.ID()
+			default:
+				us[k] = v
+			}
+		}
+		return theGraphicsDriver.DrawShader(c.dst.image.ID(), c.shader.shader.ID(), c.nindices, indexOffset, c.mode, us)
 	}
 	return theGraphicsDriver.Draw(c.dst.image.ID(), c.src.image.ID(), c.nindices, indexOffset, c.mode, c.color, c.filter, c.address)
 }
diff --git a/internal/graphicscommand/image.go b/internal/graphicscommand/image.go
index dfe6f26a8..018bc77e7 100644
--- a/internal/graphicscommand/image.go
+++ b/internal/graphicscommand/image.go
@@ -162,24 +162,17 @@ func (i *Image) DrawTriangles(src *Image, vertices []float32, indices []uint16,
 		}
 	}
 
-	var us map[int]interface{}
 	if src != nil {
 		src.resolveBufferedReplacePixels()
-	} else {
-		us = map[int]interface{}{}
-		for k, v := range uniforms {
-			switch v := v.(type) {
-			case *Image:
-				v.resolveBufferedReplacePixels()
-				us[k] = v.image
-			default:
-				us[k] = v
-			}
+	}
+	for _, v := range uniforms {
+		if img, ok := v.(*Image); ok {
+			img.resolveBufferedReplacePixels()
 		}
 	}
 	i.resolveBufferedReplacePixels()
 
-	theCommandQueue.EnqueueDrawTrianglesCommand(i, src, vertices, indices, clr, mode, filter, address, shader, us)
+	theCommandQueue.EnqueueDrawTrianglesCommand(i, src, vertices, indices, clr, mode, filter, address, shader, uniforms)
 
 	if i.lastCommand == lastCommandNone && !i.screen {
 		i.lastCommand = lastCommandClear
diff --git a/internal/graphicsdriver/opengl/graphics.go b/internal/graphicsdriver/opengl/graphics.go
index 25258b6a0..d0cca0d8b 100644
--- a/internal/graphicsdriver/opengl/graphics.go
+++ b/internal/graphicsdriver/opengl/graphics.go
@@ -16,6 +16,7 @@ package opengl
 
 import (
 	"fmt"
+	"sort"
 
 	"github.com/hajimehoshi/ebiten/internal/affine"
 	"github.com/hajimehoshi/ebiten/internal/driver"
@@ -265,8 +266,21 @@ func (g *Graphics) DrawShader(dst driver.ImageID, shader driver.ShaderID, indexL
 	g.context.blendFunc(mode)
 
 	us := map[string]interface{}{}
-	for k, v := range uniforms {
-		us[fmt.Sprintf("U%d", k)] = v
+	var keys []int
+	for k := range uniforms {
+		keys = append(keys, k)
+	}
+	sort.Ints(keys)
+	tidx := 0
+	for _, k := range keys {
+		v := uniforms[k]
+		switch v := v.(type) {
+		case driver.ImageID:
+			us[fmt.Sprintf("U%d/%d", k, tidx)] = g.images[v].textureNative
+			tidx++
+		default:
+			us[fmt.Sprintf("U%d", k)] = v
+		}
 	}
 	if err := g.useProgram(s.p, us); err != nil {
 		return err
diff --git a/internal/graphicsdriver/opengl/program.go b/internal/graphicsdriver/opengl/program.go
index 43540d698..07fd6f1ed 100644
--- a/internal/graphicsdriver/opengl/program.go
+++ b/internal/graphicsdriver/opengl/program.go
@@ -287,6 +287,8 @@ func (g *Graphics) useProgram(program program, uniforms map[string]interface{})
 				g.state.lastActiveTexture = idx
 			}
 			g.context.bindTexture(u)
+		default:
+			return fmt.Errorf("opengl: unexpected uniform value: %v", u)
 		}
 	}
 	return nil