Make safety_checker optional in more pipelines

src/diffusers/pipelines/alt_diffusion/pipeline_alt_diffusion_img2img.py

@@ -92,7 +92,7 @@ class AltDiffusionImg2ImgPipeline(DiffusionPipeline):
         feature_extractor ([`CLIPFeatureExtractor`]):
             Model that extracts features from generated images to be used as inputs for the `safety_checker`.
     """
-    _optional_components = ["safety_checker"]
+    _optional_components = ["safety_checker", "feature_extractor"]
 
     def __init__(
         self,

src/diffusers/pipelines/paint_by_example/pipeline_paint_by_example.py

@@ -161,6 +161,8 @@ class PaintByExamplePipeline(DiffusionPipeline):
         feature_extractor ([`CLIPFeatureExtractor`]):
             Model that extracts features from generated images to be used as inputs for the `safety_checker`.
     """
+    # TODO: feature_extractor is required to encode initial images (if they are in PIL format),
+    # we should give a descriptive message if the pipeline doesn't have one.
     _optional_components = ["safety_checker"]
 
     def __init__(

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_image_variation.py

@@ -65,6 +65,8 @@ class StableDiffusionImageVariationPipeline(DiffusionPipeline):
         feature_extractor ([`CLIPFeatureExtractor`]):
             Model that extracts features from generated images to be used as inputs for the `safety_checker`.
     """
+    # TODO: feature_extractor is required to encode images (if they are in PIL format),
+    # we should give a descriptive message if the pipeline doesn't have one.
     _optional_components = ["safety_checker"]
 
     def __init__(

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_img2img.py

@@ -90,7 +90,7 @@ class StableDiffusionImg2ImgPipeline(DiffusionPipeline):
         feature_extractor ([`CLIPFeatureExtractor`]):
             Model that extracts features from generated images to be used as inputs for the `safety_checker`.
     """
-    _optional_components = ["safety_checker"]
+    _optional_components = ["safety_checker", "feature_extractor"]
 
     # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.__init__
     def __init__(

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_inpaint.py

@@ -166,7 +166,7 @@ class StableDiffusionInpaintPipeline(DiffusionPipeline):
         feature_extractor ([`CLIPFeatureExtractor`]):
             Model that extracts features from generated images to be used as inputs for the `safety_checker`.
     """
-    _optional_components = ["safety_checker"]
+    _optional_components = ["safety_checker", "feature_extractor"]
 
     def __init__(
         self,