diff --git a/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_edit_inpaint.py b/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_edit_inpaint.py
index cf467203a9d2..2036ab0b19cb 100644
--- a/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_edit_inpaint.py
+++ b/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_edit_inpaint.py
@@ -870,6 +870,8 @@ def __call__(
             crops_coords = None
             resize_mode = "default"
 
+        original_image = None
+        prompt_image = None
         if image is not None and not (isinstance(image, torch.Tensor) and image.size(1) == self.latent_channels):
             image = self.image_processor.resize(image, calculated_height, calculated_width)
             original_image = image
diff --git a/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_edit_plus.py b/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_edit_plus.py
index 257e2d846c7c..dbc771bdf800 100644
--- a/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_edit_plus.py
+++ b/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_edit_plus.py
@@ -672,6 +672,10 @@ def __call__(
 
         device = self._execution_device
         # 3. Preprocess image
+        condition_image_sizes = None
+        condition_images = None
+        vae_image_sizes = None
+        vae_images = None
         if image is not None and not (isinstance(image, torch.Tensor) and image.size(1) == self.latent_channels):
             if not isinstance(image, list):
                 image = [image]
diff --git a/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_img2img.py b/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_img2img.py
index e0b41b8b8799..78e2e7f3b5ed 100644
--- a/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_img2img.py
+++ b/src/diffusers/pipelines/qwenimage/pipeline_qwenimage_img2img.py
@@ -310,6 +310,7 @@ def encode_prompt(
     def check_inputs(
         self,
         prompt,
+        image,
         strength,
         height,
         width,
@@ -321,6 +322,9 @@ def check_inputs(
         callback_on_step_end_tensor_inputs=None,
         max_sequence_length=None,
     ):
+        if image is None:
+            raise ValueError("`image` input cannot be undefined for img2img generation.")
+
         if strength < 0 or strength > 1:
             raise ValueError(f"The value of strength should in [0.0, 1.0] but is {strength}")
 
@@ -651,6 +655,7 @@ def __call__(
         # 1. Check inputs. Raise error if not correct
         self.check_inputs(
             prompt,
+            image,
             strength,
             height,
             width,
diff --git a/src/diffusers/pipelines/wan/pipeline_wan.py b/src/diffusers/pipelines/wan/pipeline_wan.py
index dc2bb471101d..100d06f8009a 100644
--- a/src/diffusers/pipelines/wan/pipeline_wan.py
+++ b/src/diffusers/pipelines/wan/pipeline_wan.py
@@ -22,7 +22,7 @@
 from ...callbacks import MultiPipelineCallbacks, PipelineCallback
 from ...loaders import WanLoraLoaderMixin
 from ...models import AutoencoderKLWan, WanTransformer3DModel
-from ...schedulers import FlowMatchEulerDiscreteScheduler
+from ...schedulers import UniPCMultistepScheduler
 from ...utils import is_ftfy_available, is_torch_xla_available, logging, replace_example_docstring
 from ...utils.torch_utils import randn_tensor
 from ...video_processor import VideoProcessor
@@ -133,7 +133,7 @@ def __init__(
         tokenizer: AutoTokenizer,
         text_encoder: UMT5EncoderModel,
         vae: AutoencoderKLWan,
-        scheduler: FlowMatchEulerDiscreteScheduler,
+        scheduler: UniPCMultistepScheduler,
         transformer: Optional[WanTransformer3DModel] = None,
         transformer_2: Optional[WanTransformer3DModel] = None,
         boundary_ratio: Optional[float] = None,
diff --git a/src/diffusers/pipelines/wan/pipeline_wan_i2v.py b/src/diffusers/pipelines/wan/pipeline_wan_i2v.py
index b7fd0b05980f..892e50776850 100644
--- a/src/diffusers/pipelines/wan/pipeline_wan_i2v.py
+++ b/src/diffusers/pipelines/wan/pipeline_wan_i2v.py
@@ -24,7 +24,7 @@
 from ...image_processor import PipelineImageInput
 from ...loaders import WanLoraLoaderMixin
 from ...models import AutoencoderKLWan, WanTransformer3DModel
-from ...schedulers import FlowMatchEulerDiscreteScheduler
+from ...schedulers import UniPCMultistepScheduler
 from ...utils import is_ftfy_available, is_torch_xla_available, logging, replace_example_docstring
 from ...utils.torch_utils import randn_tensor
 from ...video_processor import VideoProcessor
@@ -169,7 +169,7 @@ def __init__(
         tokenizer: AutoTokenizer,
         text_encoder: UMT5EncoderModel,
         vae: AutoencoderKLWan,
-        scheduler: FlowMatchEulerDiscreteScheduler,
+        scheduler: UniPCMultistepScheduler,
         image_processor: CLIPImageProcessor = None,
         image_encoder: CLIPVisionModel = None,
         transformer: WanTransformer3DModel = None,
diff --git a/src/diffusers/pipelines/wan/pipeline_wan_vace.py b/src/diffusers/pipelines/wan/pipeline_wan_vace.py
index 351ae2e70563..6936e54e98f7 100644
--- a/src/diffusers/pipelines/wan/pipeline_wan_vace.py
+++ b/src/diffusers/pipelines/wan/pipeline_wan_vace.py
@@ -24,7 +24,7 @@
 from ...image_processor import PipelineImageInput
 from ...loaders import WanLoraLoaderMixin
 from ...models import AutoencoderKLWan, WanVACETransformer3DModel
-from ...schedulers import FlowMatchEulerDiscreteScheduler
+from ...schedulers import UniPCMultistepScheduler
 from ...utils import is_ftfy_available, is_torch_xla_available, logging, replace_example_docstring
 from ...utils.torch_utils import randn_tensor
 from ...video_processor import VideoProcessor
@@ -180,7 +180,7 @@ def __init__(
         tokenizer: AutoTokenizer,
         text_encoder: UMT5EncoderModel,
         vae: AutoencoderKLWan,
-        scheduler: FlowMatchEulerDiscreteScheduler,
+        scheduler: UniPCMultistepScheduler,
         transformer: WanVACETransformer3DModel = None,
         transformer_2: WanVACETransformer3DModel = None,
         boundary_ratio: Optional[float] = None,
diff --git a/src/diffusers/pipelines/wan/pipeline_wan_video2video.py b/src/diffusers/pipelines/wan/pipeline_wan_video2video.py
index 5475b6e8b479..6dd2e9220e05 100644
--- a/src/diffusers/pipelines/wan/pipeline_wan_video2video.py
+++ b/src/diffusers/pipelines/wan/pipeline_wan_video2video.py
@@ -24,7 +24,7 @@
 from ...callbacks import MultiPipelineCallbacks, PipelineCallback
 from ...loaders import WanLoraLoaderMixin
 from ...models import AutoencoderKLWan, WanTransformer3DModel
-from ...schedulers import FlowMatchEulerDiscreteScheduler
+from ...schedulers import UniPCMultistepScheduler
 from ...utils import is_ftfy_available, is_torch_xla_available, logging, replace_example_docstring
 from ...utils.torch_utils import randn_tensor
 from ...video_processor import VideoProcessor
@@ -202,7 +202,7 @@ def __init__(
         text_encoder: UMT5EncoderModel,
         transformer: WanTransformer3DModel,
         vae: AutoencoderKLWan,
-        scheduler: FlowMatchEulerDiscreteScheduler,
+        scheduler: UniPCMultistepScheduler,
     ):
         super().__init__()