Add configuration to choose jpg/png for Allsky file.

python/lsst/pipe/tasks/hips.py

@@ -835,6 +835,15 @@ class GenerateHipsConfig(pipeBase.PipelineTaskConfig,
         default=64,
         check=_is_power_of_two,
     )
+    allsky_filetype = pexConfig.ChoiceField(
+        dtype=str,
+        doc="Allsky image file format.",
+        default="jpg",
+        allowed={
+            "jpg": "Create Allsky.jpg image.",
+            "png": "Create Allsky.png image.",
+        },
+    )
     png_gray_asinh_minimum = pexConfig.Field(
         doc="AsinhMapping intensity to be mapped to black for grayscale png scaling.",
         dtype=float,
@@ -1534,6 +1543,7 @@ def _write_allsky_file(self, hips_base_path, allsky_order):
         allsky_order : `int`
             HEALPix order of the minimum order to make allsky file.
         """
+        file_type = self.config.allsky_filetype
         tile_size = self.config.allsky_tilesize
         n_tiles_per_side = int(np.sqrt(hpg.nside_to_npixel(hpg.order_to_nside(allsky_order))))
 
@@ -1564,7 +1574,7 @@ def _write_allsky_file(self, hips_base_path, allsky_order):
                 )
             allsky_image.paste(tile_image_shrunk, box)
 
-        uri = allsky_order_uri.join("Allsky.png")
+        uri = allsky_order_uri.join(f"Allsky.{file_type}")
 
         with ResourcePath.temporary_uri(suffix=uri.getExtension()) as temporary_uri:
             allsky_image.save(temporary_uri.ospath)