clean up code & make sure the ext of thumbnail representation aligns with the image format data setting

openpype/hosts/max/api/preview_animation.py

@@ -31,7 +31,6 @@ def viewport_camera(camera):
         camera (str): viewport camera for review render
     """
     original = rt.viewport.getCamera()
-    has_autoplay = rt.preferences.playPreviewWhenDone
     if not original:
         # if there is no original camera
         # use the current camera as original
@@ -39,11 +38,9 @@ def viewport_camera(camera):
     review_camera = rt.getNodeByName(camera)
     try:
         rt.viewport.setCamera(review_camera)
-        rt.preferences.playPreviewWhenDone = False
         yield
     finally:
         rt.viewport.setCamera(original)
-        rt.preferences.playPreviewWhenDone = has_autoplay
 
 
 @contextlib.contextmanager

openpype/hosts/max/plugins/publish/extract_thumbnail.py

@@ -37,7 +37,7 @@ class ExtractThumbnail(publish.Extractor):
 
         representation = {
             "name": "thumbnail",
-            "ext": "png",
+            "ext": ext,
             "files": thumbnail,
             "stagingDir": staging_dir,
             "thumbnail": True