Got the profile picture thing working!

convex/auth.ts

@@ -1,6 +1,7 @@
 import { ConvexError, v } from 'convex/values';
 import { convexAuth, getAuthUserId } from '@convex-dev/auth/server';
 import { mutation, query } from './_generated/server';
+import { type Id } from './_generated/dataModel';
 import Password from './CustomPassword';
 
 export const { auth, signIn, signOut, store, isAuthenticated } = convexAuth({
@@ -12,19 +13,23 @@ export const getUser = query(async (ctx) => {
   if (!userId) return null;
   const user = await ctx.db.get(userId);
   if (!user) throw new ConvexError('User not found.');
+  const image: Id<'_storage'> | null =
+    typeof user.image === 'string' && user.image.length > 0
+      ? user.image as Id<'_storage'>
+      : null
   return {
     id: user._id,
     email: user.email ?? null,
     name: user.name ?? null,
-    image: user.image ?? null,
+    image,
   };
 });
 
 export const updateUserImage = mutation({
   args: {
-    storageId: v.id('_storage')
+    storageId: v.id('_storage'),
   },
-  handler: async (ctx, {storageId}) => {
+  handler: async (ctx, { storageId }) => {
     const userId = await getAuthUserId(ctx);
     if (!userId) throw new ConvexError('Not authenticated.');
     await ctx.db.patch(userId, { image: storageId });