diff --git a/ociregistry/ociclient/client.go b/ociregistry/ociclient/client.go
index 842f524..bc78b32 100644
--- a/ociregistry/ociclient/client.go
+++ b/ociregistry/ociclient/client.go
@@ -124,18 +124,25 @@ type client struct {
 	listPageSize int
 }
 
+type descriptorRequired byte
+
+const (
+	requireSize descriptorRequired = 1 << iota
+	requireDigest
+)
+
 // descriptorFromResponse tries to form a descriptor from an HTTP response,
 // filling in the Digest field using knownDigest if it's not present.
 //
 // Note: this implies that the Digest field will be empty if there is no
 // digest in the response and knownDigest is empty.
-func descriptorFromResponse(resp *http.Response, knownDigest digest.Digest, requireSize bool) (ociregistry.Descriptor, error) {
+func descriptorFromResponse(resp *http.Response, knownDigest digest.Digest, require descriptorRequired) (ociregistry.Descriptor, error) {
 	contentType := resp.Header.Get("Content-Type")
 	if contentType == "" {
 		contentType = "application/octet-stream"
 	}
 	size := int64(0)
-	if requireSize {
+	if (require & requireSize) != 0 {
 		if resp.StatusCode == http.StatusPartialContent {
 			contentRange := resp.Header.Get("Content-Range")
 			if contentRange == "" {
@@ -165,6 +172,9 @@ func descriptorFromResponse(resp *http.Response, knownDigest digest.Digest, requ
 	} else {
 		digest = knownDigest
 	}
+	if (require&requireDigest) != 0 && digest == "" {
+		return ociregistry.Descriptor{}, fmt.Errorf("no digest found in response")
+	}
 	return ociregistry.Descriptor{
 		Digest:    digest,
 		MediaType: contentType,
diff --git a/ociregistry/ociclient/reader.go b/ociregistry/ociclient/reader.go
index ba942f4..6888584 100644
--- a/ociregistry/ociclient/reader.go
+++ b/ociregistry/ociclient/reader.go
@@ -60,7 +60,7 @@ func (c *client) GetBlobRange(ctx context.Context, repo string, digest ociregist
 	// Fix that either by returning ErrUnsupported or by reading the whole
 	// blob and returning only the required portion.
 	defer closeOnError(&_err, resp.Body)
-	desc, err := descriptorFromResponse(resp, ociregistry.Digest(rreq.Digest), true)
+	desc, err := descriptorFromResponse(resp, ociregistry.Digest(rreq.Digest), requireSize)
 	if err != nil {
 		return nil, fmt.Errorf("invalid descriptor in response: %v", err)
 	}
@@ -97,7 +97,7 @@ func (c *client) resolve(ctx context.Context, rreq *ocirequest.Request) (ociregi
 		return ociregistry.Descriptor{}, err
 	}
 	resp.Body.Close()
-	desc, err := descriptorFromResponse(resp, ociregistry.Digest(rreq.Digest), true)
+	desc, err := descriptorFromResponse(resp, ociregistry.Digest(rreq.Digest), requireSize|requireDigest)
 	if err != nil {
 		return ociregistry.Descriptor{}, fmt.Errorf("invalid descriptor in response: %v", err)
 	}
@@ -138,7 +138,7 @@ func (c *client) read(ctx context.Context, rreq *ocirequest.Request) (_ ociregis
 		return nil, err
 	}
 	defer closeOnError(&_err, resp.Body)
-	desc, err := descriptorFromResponse(resp, ociregistry.Digest(rreq.Digest), true)
+	desc, err := descriptorFromResponse(resp, ociregistry.Digest(rreq.Digest), requireSize)
 	if err != nil {
 		return nil, fmt.Errorf("invalid descriptor in response: %v", err)
 	}
@@ -176,13 +176,10 @@ func (c *client) read(ctx context.Context, rreq *ocirequest.Request) (_ ociregis
 				return nil, err
 			}
 			resp1.Body.Close()
-			desc, err = descriptorFromResponse(resp1, ociregistry.Digest(rreq1.Digest), true)
+			desc, err = descriptorFromResponse(resp1, ociregistry.Digest(rreq1.Digest), requireSize|requireDigest)
 			if err != nil {
 				return nil, err
 			}
-			if desc.Digest == "" {
-				return nil, fmt.Errorf("no digest header found in response")
-			}
 		}
 	}
 	return newBlobReader(resp.Body, desc), nil
diff --git a/ociregistry/ociclient/writer.go b/ociregistry/ociclient/writer.go
index 3d8fc3c..47ac6bc 100644
--- a/ociregistry/ociclient/writer.go
+++ b/ociregistry/ociclient/writer.go
@@ -82,7 +82,8 @@ func (c *client) MountBlob(ctx context.Context, fromRepo, toRepo string, dig oci
 		// return Unsupported.
 		return ociregistry.Descriptor{}, fmt.Errorf("registry does not support mounts: %w", ociregistry.ErrUnsupported)
 	}
-	return descriptorFromResponse(resp, dig, false)
+	// TODO: is it OK to omit the size from the returned descriptor here?
+	return descriptorFromResponse(resp, dig, requireDigest)
 }
 
 func (c *client) PushBlob(ctx context.Context, repo string, desc ociregistry.Descriptor, r io.Reader) (_ ociregistry.Descriptor, _err error) {