diff --git a/exporter/containerimage/writer.go b/exporter/containerimage/writer.go
index 068d86958f8f..0c0aef743abf 100644
--- a/exporter/containerimage/writer.go
+++ b/exporter/containerimage/writer.go
@@ -178,19 +178,11 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 		return nil, err
 	}
 
-	idx := struct {
-		// MediaType is reserved in the OCI spec but
-		// excluded from go types.
-		MediaType string `json:"mediaType,omitempty"`
-
-		ocispecs.Index
-	}{
-		MediaType: ocispecs.MediaTypeImageIndex,
-		Index: ocispecs.Index{
-			Annotations: opts.Annotations.Platform(nil).Index,
-			Versioned: specs.Versioned{
-				SchemaVersion: 2,
-			},
+	idx := ocispecs.Index{
+		MediaType:   ocispecs.MediaTypeImageIndex,
+		Annotations: opts.Annotations.Platform(nil).Index,
+		Versioned: specs.Versioned{
+			SchemaVersion: 2,
 		},
 	}
 
@@ -386,24 +378,16 @@ func (ic *ImageWriter) commitDistributionManifest(ctx context.Context, opts *Ima
 		configType = images.MediaTypeDockerSchema2Config
 	}
 
-	mfst := struct {
-		// MediaType is reserved in the OCI spec but
-		// excluded from go types.
-		MediaType string `json:"mediaType,omitempty"`
-
-		ocispecs.Manifest
-	}{
-		MediaType: manifestType,
-		Manifest: ocispecs.Manifest{
-			Annotations: annotations.Manifest,
-			Versioned: specs.Versioned{
-				SchemaVersion: 2,
-			},
-			Config: ocispecs.Descriptor{
-				Digest:    configDigest,
-				Size:      int64(len(config)),
-				MediaType: configType,
-			},
+	mfst := ocispecs.Manifest{
+		MediaType:   manifestType,
+		Annotations: annotations.Manifest,
+		Versioned: specs.Versioned{
+			SchemaVersion: 2,
+		},
+		Config: ocispecs.Descriptor{
+			Digest:    configDigest,
+			Size:      int64(len(config)),
+			MediaType: configType,
 		},
 	}
 
@@ -499,23 +483,15 @@ func (ic *ImageWriter) commitAttestationsManifest(ctx context.Context, opts *Ima
 		MediaType: configType,
 	}
 
-	mfst := struct {
-		// MediaType is reserved in the OCI spec but
-		// excluded from go types.
-		MediaType string `json:"mediaType,omitempty"`
-
-		ocispecs.Manifest
-	}{
+	mfst := ocispecs.Manifest{
 		MediaType: manifestType,
-		Manifest: ocispecs.Manifest{
-			Versioned: specs.Versioned{
-				SchemaVersion: 2,
-			},
-			Config: ocispecs.Descriptor{
-				Digest:    configDigest,
-				Size:      int64(len(config)),
-				MediaType: configType,
-			},
+		Versioned: specs.Versioned{
+			SchemaVersion: 2,
+		},
+		Config: ocispecs.Descriptor{
+			Digest:    configDigest,
+			Size:      int64(len(config)),
+			MediaType: configType,
 		},
 	}
 
diff --git a/frontend/dockerfile/dockerfile_test.go b/frontend/dockerfile/dockerfile_test.go
index 9ba020f66150..57878604585f 100644
--- a/frontend/dockerfile/dockerfile_test.go
+++ b/frontend/dockerfile/dockerfile_test.go
@@ -6519,7 +6519,7 @@ FROM scratch
 COPY --from=0 / /
 `)
 
-	const expectedDigest = "sha256:9e36395384d073e711102b13bd0ba4b779ef6afbaf5cadeb77fe77dba8967d1f"
+	const expectedDigest = "sha256:23bfe9c494f4b4ae9368d989035c70b3a34aa0bfc991618b3e54dcce2eee4bf8"
 
 	dir, err := integration.Tmpdir(
 		t,