diff --git a/pyqtgraph/exporters/ImageExporter.py b/pyqtgraph/exporters/ImageExporter.py
index e600afc9..a8d235a8 100644
--- a/pyqtgraph/exporters/ImageExporter.py
+++ b/pyqtgraph/exporters/ImageExporter.py
@@ -47,10 +47,7 @@ class ImageExporter(Exporter):
     
     def export(self, fileName=None, toBytes=False, copy=False):
         if fileName is None and not toBytes and not copy:
-            if QT_LIB in ['PySide', 'PySide2']:
-                filter = ["*."+str(f, encoding='utf-8') for f in QtGui.QImageWriter.supportedImageFormats()]
-            else:
-                filter = ["*."+bytes(f).decode('utf-8') for f in QtGui.QImageWriter.supportedImageFormats()]
+            filter    = ["*."+f.data().decode('utf-8') for f in QtGui.QImageWriter.supportedImageFormats()]
             preferred = ['*.png', '*.tif', '*.jpg']
             for p in preferred[::-1]:
                 if p in filter:
diff --git a/pyqtgraph/exporters/tests/test_image.py b/pyqtgraph/exporters/tests/test_image.py
new file mode 100644
index 00000000..6f52eceb
--- /dev/null
+++ b/pyqtgraph/exporters/tests/test_image.py
@@ -0,0 +1,13 @@
+# -*- coding: utf-8 -*-
+import pyqtgraph as pg
+from pyqtgraph.exporters import ImageExporter
+
+app = pg.mkQApp()
+
+
+def test_ImageExporter_filename_dialog():
+    """Tests ImageExporter code path that opens a file dialog. Regression test
+    for pull request 1133."""
+    p = pg.plot()
+    exp = ImageExporter(p.getPlotItem())
+    exp.export()