WIP re: gradio-app#7486. Make less PNG-centric.

preserve file format during upload
add format to image component

gradio/components/image.py

@@ -41,6 +41,7 @@ class Image(StreamingInput, Component):
 
     def __init__(
         self,
+        format: str | None = None,
         value: str | PIL.Image.Image | np.ndarray | None = None,
         *,
         height: int | str | None = None,
@@ -69,6 +70,7 @@ def __init__(
         """
         Parameters:
             value: A PIL Image, numpy array, path or URL for the default value that Image component is going to take. If callable, the function will be called whenever the app loads to set the initial value of the component.
+            format: Format of to be returned by component, such as 'jpg' or 'png'. If set to None, image will keep uploaded format.
             height: The height of the displayed image, specified in pixels if a number is passed, or in CSS units if a string is passed.
             width: The width of the displayed image, specified in pixels if a number is passed, or in CSS units if a string is passed.
             image_mode: "RGB" if color, or "L" if black and white. See https://pillow.readthedocs.io/en/stable/handbook/concepts.html for other supported image modes and their meaning.
@@ -90,6 +92,7 @@ def __init__(
             mirror_webcam: If True webcam will be mirrored. Default is True.
             show_share_button: If True, will show a share icon in the corner of the component that allows user to share outputs to Hugging Face Spaces Discussions. If False, icon does not appear. If set to None (default behavior), then the icon appears if this Gradio app is launched on Spaces, but not otherwise.
         """
+        self.format = format
         self.mirror_webcam = mirror_webcam
         valid_types = ["numpy", "pil", "filepath"]
         if type not in valid_types:

gradio/processing_utils.py

@@ -58,12 +58,17 @@ def extract_base64_data(x: str) -> str:
 #########################
 
 
-def encode_plot_to_base64(plt):
+def encode_plot_to_base64(plt, format="png"):
     with BytesIO() as output_bytes:
-        plt.savefig(output_bytes, format="png")
+        plt.savefig(output_bytes, format)
         bytes_data = output_bytes.getvalue()
     base64_str = str(base64.b64encode(bytes_data), "utf-8")
-    return "data:image/png;base64," + base64_str
+    return format_base64_str(base64_str, format)
+
+
+def get_pil_exif_bytes(pil_image):
+    if "exif" in pil_image.info:
+        return pil_image.info["exif"]
 
 
 def get_pil_metadata(pil_image):
@@ -78,23 +83,31 @@ def get_pil_metadata(pil_image):
 
 def encode_pil_to_bytes(pil_image, format="png"):
     with BytesIO() as output_bytes:
-        pil_image.save(output_bytes, format, pnginfo=get_pil_metadata(pil_image))
+        if format == "png":
+            params = {"pnginfo": get_pil_metadata(pil_image)}
+        else:
+            params = {"exif": get_pil_exif_bytes(pil_image)}
+        pil_image.save(output_bytes, format, **params)
         return output_bytes.getvalue()
 
 
-def encode_pil_to_base64(pil_image):
-    bytes_data = encode_pil_to_bytes(pil_image)
+def encode_pil_to_base64(pil_image, format="png"):
+    bytes_data = encode_pil_to_bytes(pil_image, format)
     base64_str = str(base64.b64encode(bytes_data), "utf-8")
-    return "data:image/png;base64," + base64_str
+    return format_base64_str(base64_str, format)
 
 
-def encode_array_to_base64(image_array):
+def encode_array_to_base64(image_array, format="png"):
     with BytesIO() as output_bytes:
         pil_image = Image.fromarray(_convert(image_array, np.uint8, force_copy=False))
-        pil_image.save(output_bytes, "PNG")
+        pil_image.save(output_bytes, format)
         bytes_data = output_bytes.getvalue()
     base64_str = str(base64.b64encode(bytes_data), "utf-8")
-    return "data:image/png;base64," + base64_str
+    return format_base64_str(base64_str, format)
+
+
+def format_base64_str(data, format=None) -> str:
+    return f"data:image/{format or 'png'};base64,{data}"
 
 
 def hash_file(file_path: str | Path, chunk_num_blocks: int = 128) -> str: