diff --git a/sloth/annotations/container.py b/sloth/annotations/container.py
index 64d9b3a..9512586 100644
--- a/sloth/annotations/container.py
+++ b/sloth/annotations/container.py
@@ -203,7 +203,6 @@ class PickleContainer(AnnotationContainer):
         """
         Overwritten to write pickle files.
         """
-        # TODO make all image filenames relative to the label file
         f = open(fname, "wb")
         pickle.dump(annotations, f)
 
@@ -292,7 +291,6 @@ class OkapiAnnotationContainer(AnnotationContainer):
                         fileitem.frames().push_back(frameitem)
             container.files().push_back(fileitem)
 
-        # TODO make all image filenames relative to the label file
         container.WriteToFile(fname)
 
 
@@ -312,7 +310,6 @@ class JsonContainer(AnnotationContainer):
         """
         Overwritten to write JSON files.
         """
-        # TODO make all image filenames relative to the label file
         f = open(fname, "w")
         json.dump(annotations, f, indent=4, separators=(',', ': '), sort_keys=True)
 
@@ -356,7 +353,6 @@ class YamlContainer(AnnotationContainer):
         """
         Overwritten to write YAML files.
         """
-        # TODO make all image filenames relative to the label file
         f = open(fname, "w")
         yaml.dump(annotations, f)
 
@@ -417,8 +413,6 @@ class FeretContainer(AnnotationContainer):
         """
         Not implemented yet.
         """
-        # TODO make sure the image paths are
-        # relative to the label file's directory
         raise NotImplemented(
             "FeretContainer.serializeToFile() is not implemented yet."
         )
diff --git a/sloth/gui/labeltool.py b/sloth/gui/labeltool.py
index 16ab069..036838c 100644
--- a/sloth/gui/labeltool.py
+++ b/sloth/gui/labeltool.py
@@ -384,6 +384,9 @@ class MainWindow(QMainWindow):
 
         fname = str(fname)
 
+        if os.path.isabs(fname):
+            fname = os.path.relpath(fname, str(path))
+
         for pattern in image_types:
             if fnmatch.fnmatch(fname, pattern):
                 return self.labeltool.addImageFile(fname)