@@ -89,6 +89,76 @@ func BenchmarkImageList(b *testing.B) {

 	}

 }

+func TestImageListCheckTotalSize(t *testing.T) {

+	ctx := namespaces.WithNamespace(context.TODO(), "testing")

+

+	blobsDir := t.TempDir()

+	cs := &blobsDirContentStore{blobs: filepath.Join(blobsDir, "blobs/sha256")}

+

+	twoplatform, mfstsDescs, err := specialimage.MultiPlatform(blobsDir, "test:latest", []ocispec.Platform{

+		{OS: "linux", Architecture: "arm64"},

+		{OS: "linux", Architecture: "amd64"},

+	})

+	assert.NilError(t, err)

+

+	ctx = logtest.WithT(ctx, t)

+	service := fakeImageService(t, ctx, cs)

+

+	_, err = service.images.Create(ctx, imagesFromIndex(twoplatform)[0])

+	assert.NilError(t, err)

+

+	all, err := service.Images(ctx, imagetypes.ListOptions{Manifests: true})

+	assert.NilError(t, err)

+

+	assert.Check(t, is.Len(all, 1))

+	assert.Check(t, is.Len(all[0].Manifests, 2))

+

+	// TODO: The test snapshotter doesn't do anything, so the size is always 0.

+	assert.Check(t, is.Equal(all[0].Manifests[0].ImageData.Size.Unpacked, int64(0)))

+	assert.Check(t, is.Equal(all[0].Manifests[1].ImageData.Size.Unpacked, int64(0)))

+

+	mfstArm64 := mfstsDescs[0]

+	mfstAmd64 := mfstsDescs[1]

+

+	indexSize := blobSize(t, ctx, cs, twoplatform.Manifests[0].Digest)

+	arm64ManifestSize := blobSize(t, ctx, cs, mfstArm64.Digest)

+	amd64ManifestSize := blobSize(t, ctx, cs, mfstAmd64.Digest)

+

+	var arm64Mfst, amd64Mfst ocispec.Manifest

+	assert.NilError(t, readConfig(ctx, cs, mfstArm64, &arm64Mfst))

+	assert.NilError(t, readConfig(ctx, cs, mfstAmd64, &amd64Mfst))

+

+	// MultiPlatform should produce a single layer. If these fail, the test needs to be adjusted.

+	assert.Assert(t, is.Len(arm64Mfst.Layers, 1))

+	assert.Assert(t, is.Len(amd64Mfst.Layers, 1))

+

+	arm64ConfigSize := blobSize(t, ctx, cs, arm64Mfst.Config.Digest)

+	amd64ConfigSize := blobSize(t, ctx, cs, amd64Mfst.Config.Digest)

+

+	arm64LayerSize := blobSize(t, ctx, cs, arm64Mfst.Layers[0].Digest)

+	amd64LayerSize := blobSize(t, ctx, cs, amd64Mfst.Layers[0].Digest)

+

+	allTotalSize := indexSize +

+		arm64ManifestSize + amd64ManifestSize +

+		arm64ConfigSize + amd64ConfigSize +

+		arm64LayerSize + amd64LayerSize

+

+	assert.Check(t, is.Equal(all[0].Size, allTotalSize-indexSize))

+

+	assert.Check(t, is.Equal(all[0].Manifests[0].Size.Content, arm64ManifestSize+arm64ConfigSize+arm64LayerSize))

+	assert.Check(t, is.Equal(all[0].Manifests[1].Size.Content, amd64ManifestSize+amd64ConfigSize+amd64LayerSize))

+

+	// TODO: This should also include the Size.Unpacked, but the test snapshotter doesn't do anything yet

+	assert.Check(t, is.Equal(all[0].Manifests[0].Size.Total, amd64ManifestSize+amd64ConfigSize+amd64LayerSize))

+	assert.Check(t, is.Equal(all[0].Manifests[1].Size.Total, amd64ManifestSize+amd64ConfigSize+amd64LayerSize))

+}

+

+func blobSize(t *testing.T, ctx context.Context, cs content.Store, dgst digest.Digest) int64 {

+	info, err := cs.Info(ctx, dgst)

+	assert.NilError(t, err)

+	return info.Size

+}

+

 func TestImageList(t *testing.T) {

 	ctx := namespaces.WithNamespace(context.TODO(), "testing")

@@ -204,7 +204,7 @@ func TestImagePushIndex(t *testing.T) {

 				imgSvc.defaultPlatformOverride = platforms.Only(defaultDaemonPlatform)

 			}

-			idx, err := specialimage.MultiPlatform(csDir, "multiplatform:latest", tc.indexPlatforms)

+			idx, _, err := specialimage.MultiPlatform(csDir, "multiplatform:latest", tc.indexPlatforms)

 			assert.NilError(t, err)

 			imgs := imagesFromIndex(idx)

@@ -251,7 +251,8 @@ func TestAPIImagesListManifests(t *testing.T) {

 		{OS: "darwin", Architecture: "arm64"},

 	}

 	specialimage.Load(ctx, t, apiClient, func(dir string) (*ocispec.Index, error) {

-		return specialimage.MultiPlatform(dir, "multiplatform:latest", testPlatforms)

+		idx, _, err := specialimage.MultiPlatform(dir, "multiplatform:latest", testPlatforms)

+		return idx, err

 	})

 	t.Run("unsupported before 1.47", func(t *testing.T) {

@@ -7,10 +7,10 @@ import (

 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"

 )

-func MultiPlatform(dir string, imageRef string, imagePlatforms []ocispec.Platform) (*ocispec.Index, error) {

+func MultiPlatform(dir string, imageRef string, imagePlatforms []ocispec.Platform) (*ocispec.Index, []ocispec.Descriptor, error) {

 	ref, err := reference.ParseNormalizedNamed(imageRef)

 	if err != nil {

-		return nil, err

+		return nil, nil, err

 	}

 	var descs []ocispec.Descriptor

@@ -19,14 +19,15 @@ func MultiPlatform(dir string, imageRef string, imagePlatforms []ocispec.Platfor

 		ps := platforms.Format(platform)

 		manifestDesc, err := oneLayerPlatformManifest(dir, platform, FileInLayer{Path: "bash", Content: []byte("layer-" + ps)})

 		if err != nil {

-			return nil, err

+			return nil, nil, err

 		}

 		descs = append(descs, manifestDesc)

 	}

-	return multiPlatformImage(dir, ref, ocispec.Index{

+	idx, err := multiPlatformImage(dir, ref, ocispec.Index{

 		Versioned: specs.Versioned{SchemaVersion: 2},

 		MediaType: ocispec.MediaTypeImageIndex,

 		Manifests: descs,

 	})

+	return idx, descs, err

 }