diff --git a/src/kbmod/image_collection.py b/src/kbmod/image_collection.py
index dce44354d..00e711720 100644
--- a/src/kbmod/image_collection.py
+++ b/src/kbmod/image_collection.py
@@ -885,10 +885,18 @@ def toWorkUnit(self, search_config=None, **kwargs):
 
         logger.info("Building WorkUnit from ImageCollection")
         layeredImages = []
+        locations = []
         for std in self.get_standardizers(**kwargs):
+            location = std["std"].location
             for img in std["std"].toLayeredImage():
                 layeredImages.append(img)
+                locations.append(location)
         imgstack = ImageStack(layeredImages)
-        if None not in self.wcs:
-            return WorkUnit(imgstack, search_config, per_image_wcs=list(self.wcs))
-        return WorkUnit(imgstack, search_config)
+        per_img_wcs = list(self.wcs) if None not in self.wcs else None
+
+        return WorkUnit(
+            imgstack,
+            search_config,
+            per_image_wcs=per_img_wcs,
+            constituent_images=locations,
+        )
diff --git a/tests/test_imagecollection.py b/tests/test_imagecollection.py
index d320e5d0a..9ff0bd688 100644
--- a/tests/test_imagecollection.py
+++ b/tests/test_imagecollection.py
@@ -156,6 +156,11 @@ def test_workunit(self):
         data = self.fitsFactory.get_n(3, spoof_data=True)
         ic = ImageCollection.fromTargets(data)
         wu = ic.toWorkUnit(search_config=SearchConfiguration())
+        self.assertEqual(len(wu), 3)
+        for loc in wu.constituent_images:
+            self.assertEqual(loc, ":memory:")
+
+        # Write out the WorkUnit.
         with tempfile.TemporaryDirectory() as dir_name:
             wu.to_fits(f"{dir_name}/test.fits")