diff --git a/web/packages/new/photos/services/ml/face.ts b/web/packages/new/photos/services/ml/face.ts
index 7ecbf06002..891b605db2 100644
--- a/web/packages/new/photos/services/ml/face.ts
+++ b/web/packages/new/photos/services/ml/face.ts
@@ -139,6 +139,17 @@ export interface Face {
      * This ID is guaranteed to be unique for all the faces detected in all the
      * files for the user. In particular, each file can have multiple faces but
      * they all will get their own unique {@link faceID}.
+     *
+     * This ID is also meant to be stable across reindexing. That is, if the
+     * same algorithm and hyperparameters are used to reindex the file, then it
+     * should result in the same face IDs. This allows us leeway in letting
+     * unnecessary reindexing happen in rare cases without invalidating the
+     * clusters that rely on the presence of the given face ID.
+     *
+     * Finally, this face ID is not completely opaque. It consists of underscore
+     * separated components, the first of which is the ID of the
+     * {@link EnteFile} to which this face belongs. Client code can rely on this
+     * structure and can parse it if needed.
      */
     faceID: string;
     /**
diff --git a/web/packages/new/photos/services/ml/index.ts b/web/packages/new/photos/services/ml/index.ts
index 03e39343fb..584c447b40 100644
--- a/web/packages/new/photos/services/ml/index.ts
+++ b/web/packages/new/photos/services/ml/index.ts
@@ -3,6 +3,7 @@
  */
 
 import { isDesktop } from "@/base/app";
+import { assertionFailed } from "@/base/assert";
 import { blobCache } from "@/base/blob-cache";
 import { ensureElectron } from "@/base/electron";
 import { isDevBuild } from "@/base/env";
@@ -69,6 +70,11 @@ class MLState {
      * See {@link mlStatusSnapshot}.
      */
     mlStatusSnapshot: MLStatus | undefined;
+
+    /**
+     * IDs files for which we are currently regenerating face crops.
+     */
+    inFlightFaceCropRegenFileIDs = new Set<number>();
 }
 
 /** State shared by the functions in this module. See {@link MLState}. */
@@ -481,6 +487,28 @@ export const unidentifiedFaceIDs = async (
     return index?.faces.map((f) => f.faceID) ?? [];
 };
 
+/**
+ * Return the cached face crop for the given face, regenerating it if needed.
+ *
+ * @param faceID The id of the face whose face crop we want.
+ */
+export const faceCrop = (faceID: string) => {
+    const fileID = fileIDFromFaceID(faceID);
+};
+
+/**
+ * Extract the ID of the {@link EnteFile} to which this face belongs from the
+ * given {@link faceID}.
+ */
+const fileIDFromFaceID = (faceID: string) => {
+    const fileID = parseInt(faceID.split("_")[0] ?? "");
+    if (isNaN(fileID)) {
+        assertionFailed(`Ignoring attempt to parse invalid faceID ${faceID}`);
+        return undefined;
+    }
+    return fileID;
+};
+
 /**
  * Check to see if any of the faces in the given file do not have a face crop
  * present locally. If so, then regenerate the face crops for all the faces in