diff --git a/internal/photoprism/colors.go b/internal/photoprism/colors.go
index 4170d2df2..e08bde6eb 100644
--- a/internal/photoprism/colors.go
+++ b/internal/photoprism/colors.go
@@ -27,6 +27,19 @@ func (m *MediaFile) Colors(thumbPath string) (perception colors.ColorPerception,
 
 	bounds := img.Bounds()
 	width, height := bounds.Max.X, bounds.Max.Y
+
+	// Enforce thumbnail width limit and warn if it is exceeded.
+	if maxWidth := thumb.SizeColors.Width; width > maxWidth {
+		log.Warnf("color: thumbnail width %d exceeds size limit of %d in %s", width, maxWidth, clean.Log(m.RootRelName()))
+		width = maxWidth
+	}
+
+	// Enforce thumbnail height limit and warn if it is exceeded.
+	if maxHeight := thumb.SizeColors.Height; height > maxHeight {
+		log.Warnf("color: thumbnail height %d exceeds size limit of %d in %s", height, maxHeight, clean.Log(m.RootRelName()))
+		height = maxHeight
+	}
+
 	pixels := float64(width * height)
 	chromaSum := 0.0
 
diff --git a/internal/photoprism/colors_test.go b/internal/photoprism/colors_test.go
index 5b2b69df3..d47adf977 100644
--- a/internal/photoprism/colors_test.go
+++ b/internal/photoprism/colors_test.go
@@ -9,6 +9,7 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"github.com/photoprism/photoprism/internal/config"
+	"github.com/photoprism/photoprism/internal/thumb"
 	"github.com/photoprism/photoprism/pkg/colors"
 	"github.com/photoprism/photoprism/pkg/fastwalk"
 )
@@ -101,84 +102,105 @@ func TestMediaFile_Colors_Testdata(t *testing.T) {
 }
 
 func TestMediaFile_Colors(t *testing.T) {
-	conf := config.TestConfig()
+	c := config.TestConfig()
 
 	t.Run("cat_brown.jpg", func(t *testing.T) {
-		if mediaFile, err := NewMediaFile(conf.ExamplesPath() + "/cat_brown.jpg"); err == nil {
-			p, err := mediaFile.Colors(conf.ThumbCachePath())
+		if mediaFile, err := NewMediaFile(c.ExamplesPath() + "/cat_brown.jpg"); err == nil {
+			file, fileErr := mediaFile.Colors(c.ThumbCachePath())
 
-			t.Log(p, err)
+			t.Log(file, fileErr)
 
-			assert.Nil(t, err)
-			assert.Equal(t, 13, p.Chroma.Int())
-			assert.Equal(t, "D", p.Chroma.Hex())
-			assert.IsType(t, colors.Colors{}, p.Colors)
-			assert.Equal(t, "gold", p.MainColor.Name())
-			assert.Equal(t, colors.Colors{0x9, 0x3, 0x2, 0x1, 0x1, 0x2, 0x0, 0x6, 0x1}, p.Colors)
-			assert.Equal(t, colors.LightMap{0x4, 0x5, 0xb, 0x4, 0x7, 0x3, 0x2, 0x5, 0x7}, p.Luminance)
+			assert.Nil(t, fileErr)
+			assert.Equal(t, 13, file.Chroma.Int())
+			assert.Equal(t, "D", file.Chroma.Hex())
+			assert.IsType(t, colors.Colors{}, file.Colors)
+			assert.Equal(t, "gold", file.MainColor.Name())
+			assert.Equal(t, colors.Colors{0x9, 0x3, 0x2, 0x1, 0x1, 0x2, 0x0, 0x6, 0x1}, file.Colors)
+			assert.Equal(t, colors.LightMap{0x4, 0x5, 0xb, 0x4, 0x7, 0x3, 0x2, 0x5, 0x7}, file.Luminance)
 		} else {
 			t.Error(err)
 		}
 	})
+	t.Run("FernRegular", func(t *testing.T) {
+		if mediaFile, err := NewMediaFile(c.ExamplesPath() + "/fern_green.jpg"); err == nil {
+			file, fileErr := mediaFile.Colors(c.ThumbCachePath())
 
-	t.Run("fern_green.jpg", func(t *testing.T) {
-		if mediaFile, err := NewMediaFile(conf.ExamplesPath() + "/fern_green.jpg"); err == nil {
-			p, err := mediaFile.Colors(conf.ThumbCachePath())
+			t.Log(file, fileErr)
 
-			t.Log(p, err)
-
-			assert.Nil(t, err)
-			assert.Equal(t, 51, p.Chroma.Int())
-			assert.Equal(t, "33", p.Chroma.Hex())
-			assert.IsType(t, colors.Colors{}, p.Colors)
-			assert.Equal(t, "lime", p.MainColor.Name())
-			assert.Equal(t, colors.Colors{0xa, 0x9, 0xa, 0x9, 0xa, 0xa, 0x9, 0x9, 0x9}, p.Colors)
-			assert.Equal(t, colors.LightMap{0xb, 0x4, 0xa, 0x6, 0x9, 0x8, 0x2, 0x3, 0x4}, p.Luminance)
+			assert.Nil(t, fileErr)
+			assert.Equal(t, 51, file.Chroma.Int())
+			assert.Equal(t, "33", file.Chroma.Hex())
+			assert.IsType(t, colors.Colors{}, file.Colors)
+			assert.Equal(t, "lime", file.MainColor.Name())
+			assert.Equal(t, colors.Colors{0xa, 0x9, 0xa, 0x9, 0xa, 0xa, 0x9, 0x9, 0x9}, file.Colors)
+			assert.Equal(t, colors.LightMap{0xb, 0x4, 0xa, 0x6, 0x9, 0x8, 0x2, 0x3, 0x4}, file.Luminance)
 		} else {
 			t.Error(err)
 		}
 	})
+	t.Run("FernLarge", func(t *testing.T) {
+		if mediaFile, err := NewMediaFile(c.ExamplesPath() + "/fern_green.jpg"); err == nil {
+			thumbLarge := thumb.SizeColors
+			thumbLarge.Height = 16
+			thumbLarge.Width = 16
+			thumbLarge.Name = "color_large"
 
+			thumb.Sizes[thumb.Colors] = thumbLarge
+
+			file, fileErr := mediaFile.Colors(c.ThumbCachePath())
+
+			thumb.Sizes[thumb.Colors] = thumb.SizeColors
+
+			t.Log(file, fileErr)
+
+			assert.Nil(t, fileErr)
+			assert.Equal(t, 67, file.Chroma.Int())
+			assert.Equal(t, "43", file.Chroma.Hex())
+			assert.IsType(t, colors.Colors{}, file.Colors)
+			assert.Equal(t, "lime", file.MainColor.Name())
+			assert.Equal(t, colors.Colors{9, 10, 10, 10, 10, 10, 10, 10, 10}, file.Colors)
+			assert.Equal(t, colors.LightMap{5, 9, 9, 9, 9, 10, 10, 9, 11}, file.Luminance)
+		} else {
+			t.Error(err)
+		}
+	})
 	t.Run("IMG_4120.JPG", func(t *testing.T) {
-		if mediaFile, err := NewMediaFile(conf.ExamplesPath() + "/IMG_4120.JPG"); err == nil {
-			p, err := mediaFile.Colors(conf.ThumbCachePath())
+		if mediaFile, err := NewMediaFile(c.ExamplesPath() + "/IMG_4120.JPG"); err == nil {
+			file, fileErr := mediaFile.Colors(c.ThumbCachePath())
 
-			t.Log(p, err)
+			t.Log(file, fileErr)
 
-			assert.Nil(t, err)
-			assert.Equal(t, 7, p.Chroma.Int())
-			assert.Equal(t, "7", p.Chroma.Hex())
-			assert.IsType(t, colors.Colors{}, p.Colors)
-			assert.Equal(t, "blue", p.MainColor.Name())
-			assert.Equal(t, colors.Colors{0x1, 0x6, 0x6, 0x1, 0x1, 0x9, 0x1, 0x0, 0x0}, p.Colors)
+			assert.Nil(t, fileErr)
+			assert.Equal(t, 7, file.Chroma.Int())
+			assert.Equal(t, "7", file.Chroma.Hex())
+			assert.IsType(t, colors.Colors{}, file.Colors)
+			assert.Equal(t, "blue", file.MainColor.Name())
+			assert.Equal(t, colors.Colors{0x1, 0x6, 0x6, 0x1, 0x1, 0x9, 0x1, 0x0, 0x0}, file.Colors)
 		} else {
 			t.Error(err)
 		}
 	})
-
 	t.Run("leaves_gold.jpg", func(t *testing.T) {
-		if mediaFile, err := NewMediaFile(conf.ExamplesPath() + "/leaves_gold.jpg"); err == nil {
-			p, err := mediaFile.Colors(conf.ThumbCachePath())
+		if mediaFile, err := NewMediaFile(c.ExamplesPath() + "/leaves_gold.jpg"); err == nil {
+			file, fileErr := mediaFile.Colors(c.ThumbCachePath())
 
-			t.Log(p, err)
+			t.Log(file, fileErr)
 
-			assert.Nil(t, err)
-			assert.Equal(t, 16, p.Chroma.Int())
-			assert.Equal(t, "10", p.Chroma.Hex())
-			assert.IsType(t, colors.Colors{}, p.Colors)
-			assert.Equal(t, "gold", p.MainColor.Name())
+			assert.Nil(t, fileErr)
+			assert.Equal(t, 16, file.Chroma.Int())
+			assert.Equal(t, "10", file.Chroma.Hex())
+			assert.IsType(t, colors.Colors{}, file.Colors)
+			assert.Equal(t, "gold", file.MainColor.Name())
 
-			assert.Equal(t, colors.Colors{0x0, 0x0, 0x2, 0x3, 0x3, 0x0, 0x2, 0x3, 0x0}, p.Colors)
+			assert.Equal(t, colors.Colors{0x0, 0x0, 0x2, 0x3, 0x3, 0x0, 0x2, 0x3, 0x0}, file.Colors)
 		} else {
 			t.Error(err)
 		}
 	})
-
 	t.Run("Random.docx", func(t *testing.T) {
-		mediaFile, err := NewMediaFile(conf.ExamplesPath() + "/Random.docx")
-		p, err := mediaFile.Colors(conf.ThumbCachePath())
-		assert.Error(t, err, "no color information: not a JPEG file")
+		file, fileErr := NewMediaFile(c.ExamplesPath() + "/Random.docx")
+		p, fileErr := file.Colors(c.ThumbCachePath())
+		assert.Error(t, fileErr, "no color information: not a JPEG file")
 		t.Log(p)
-
 	})
 }
diff --git a/internal/thumb/sizes.go b/internal/thumb/sizes.go
index 2e337510d..7eb11c63e 100644
--- a/internal/thumb/sizes.go
+++ b/internal/thumb/sizes.go
@@ -37,15 +37,25 @@ func (m SizeMap) All() SizeList {
 	return result
 }
 
+var (
+	SizeTile50   = Size{Tile50, Tile500, "List View", 50, 50, false, false, []ResampleOption{ResampleFillCenter, ResampleDefault}}
+	SizeTile100  = Size{Tile100, Tile500, "Places View", 100, 100, false, false, []ResampleOption{ResampleFillCenter, ResampleDefault}}
+	SizeTile224  = Size{Tile224, Tile500, "TensorFlow, Mosaic View", 224, 224, false, false, []ResampleOption{ResampleFillCenter, ResampleDefault}}
+	SizeTile500  = Size{Tile500, "", "Cards View", 500, 500, false, false, []ResampleOption{ResampleFillCenter, ResampleDefault}}
+	SizeColors   = Size{Colors, Fit720, "Color Detection", 3, 3, false, false, []ResampleOption{ResampleResize, ResampleNearestNeighbor, ResamplePng}}
+	SizeLeft224  = Size{Left224, Fit720, "TensorFlow", 224, 224, false, false, []ResampleOption{ResampleFillTopLeft, ResampleDefault}}
+	SizeRight224 = Size{Right224, Fit720, "TensorFlow", 224, 224, false, false, []ResampleOption{ResampleFillBottomRight, ResampleDefault}}
+)
+
 // Sizes contains the properties of all thumbnail sizes.
 var Sizes = SizeMap{
-	Tile50:   {Tile50, Tile500, "List View", 50, 50, false, false, []ResampleOption{ResampleFillCenter, ResampleDefault}},
-	Tile100:  {Tile100, Tile500, "Places View", 100, 100, false, false, []ResampleOption{ResampleFillCenter, ResampleDefault}},
-	Tile224:  {Tile224, Tile500, "TensorFlow, Mosaic View", 224, 224, false, false, []ResampleOption{ResampleFillCenter, ResampleDefault}},
-	Tile500:  {Tile500, "", "Cards View", 500, 500, false, false, []ResampleOption{ResampleFillCenter, ResampleDefault}},
-	Colors:   {Colors, Fit720, "Color Detection", 3, 3, false, false, []ResampleOption{ResampleResize, ResampleNearestNeighbor, ResamplePng}},
-	Left224:  {Left224, Fit720, "TensorFlow", 224, 224, false, false, []ResampleOption{ResampleFillTopLeft, ResampleDefault}},
-	Right224: {Right224, Fit720, "TensorFlow", 224, 224, false, false, []ResampleOption{ResampleFillBottomRight, ResampleDefault}},
+	Tile50:   SizeTile50,
+	Tile100:  SizeTile100,
+	Tile224:  SizeTile224,
+	Tile500:  SizeTile500,
+	Colors:   SizeColors,
+	Left224:  SizeLeft224,
+	Right224: SizeRight224,
 	Fit720:   {Fit720, "", "SD TV, Mobile", 720, 720, true, true, []ResampleOption{ResampleFit, ResampleDefault}},
 	Fit1280:  {Fit1280, Fit2048, "HD TV, SXGA", 1280, 1024, true, true, []ResampleOption{ResampleFit, ResampleDefault}},
 	Fit1920:  {Fit1920, Fit2048, "Full HD", 1920, 1200, true, true, []ResampleOption{ResampleFit, ResampleDefault}},
diff --git a/pkg/colors/colors.go b/pkg/colors/colors.go
index d67af5065..981a5c868 100644
--- a/pkg/colors/colors.go
+++ b/pkg/colors/colors.go
@@ -118,6 +118,10 @@ func (c Color) ID() int16 {
 }
 
 func (c Color) Hex() string {
+	if c < 0 || c > 15 {
+		return "0"
+	}
+
 	return fmt.Sprintf("%X", c)
 }
 
diff --git a/pkg/colors/colors_test.go b/pkg/colors/colors_test.go
index ed6693c94..5d1262ad4 100644
--- a/pkg/colors/colors_test.go
+++ b/pkg/colors/colors_test.go
@@ -19,13 +19,23 @@ func TestColors_List(t *testing.T) {
 }
 
 func TestColor_Hex(t *testing.T) {
+	assert.Equal(t, "0", Color(-1).Hex())
+	assert.Equal(t, "0", Black.Hex())
 	assert.Equal(t, "C", Magenta.Hex())
 	assert.Equal(t, "7", Cyan.Hex())
+	assert.Equal(t, "F", Pink.Hex())
+	assert.Equal(t, "F", Color(15).Hex())
+	assert.Equal(t, "0", Color(16).Hex())
+	assert.Equal(t, "0", Color(17).Hex())
 }
 
 func TestColors_Hex(t *testing.T) {
-	result := Colors{Orange, Lime, Black}.Hex()
-	assert.Equal(t, "DA0", result)
+	t.Run("All", func(t *testing.T) {
+		assert.Equal(t, "5CFED3BA98762410", All.Hex())
+	})
+	t.Run("OrangeLimeBlack", func(t *testing.T) {
+		assert.Equal(t, "DA0", Colors{Orange, Lime, Black}.Hex())
+	})
 }
 
 func TestColor_ID(t *testing.T) {
diff --git a/pkg/colors/perception.go b/pkg/colors/perception.go
index 5be43206e..607f8b3f9 100644
--- a/pkg/colors/perception.go
+++ b/pkg/colors/perception.go
@@ -1,6 +1,6 @@
 package colors
 
-// Information on how an image looks like in terms of colors and light.
+// ColorPerception provides information on how an image looks in terms of color and light.
 type ColorPerception struct {
 	Colors    Colors
 	MainColor Color