update image if title or subtitle changes

hcatitles.py

@@ -64,11 +64,24 @@ def main():
     layout = build_layout(title, subtitle, thumbnail)
     window = sg.Window('Harvest Christian Assembly Message Title', layout)
 
+    # image contains the final image
     while True:
         event, values = window.read(timeout=50)
         if event == sg.WIN_CLOSED:
             break
 
+        if event == "-TITLE-" or event == '-SUBTITLE-':
+            if values['-TITLE-'] != title or values['-SUBTITLE-'] != subtitle:
+                title = values['-TITLE-']
+                subtitle = values['-SUBTITLE-']
+                original = Image.open(image_path)
+                image = update_image(original, title, subtitle)
+                thumbnail = update_thumbnail(image)
+                bio = BytesIO()
+                thumbnail.save(bio, format = 'PNG')
+                window['-IMAGE-'].update(data = bio.getvalue())
+
+
         if event == "-SAVE-":
             save_path = sg.popup_get_file('Save',
                                           save_as = True,