update prepare_latents from flux.img2img pipeline

Author: Suprhimp

src/diffusers/pipelines/flux/pipeline_flux_fill.py

@@ -224,11 +224,11 @@ def __init__(
         self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1) if getattr(self, "vae", None) else 8
         # Flux latents are turned into 2x2 patches and packed. This means the latent width and height has to be divisible
         # by the patch size. So the vae scale factor is multiplied by the patch size to account for this
-        self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor * 2)
-        latent_channels = self.vae.config.latent_channels if getattr(self, "vae", None) else 16
+        self.latent_channels = self.vae.config.latent_channels if getattr(self, "vae", None) else 16
+        self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor * 2,vae_latent_channels=self.latent_channels)
         self.mask_processor = VaeImageProcessor(
             vae_scale_factor=self.vae_scale_factor * 2,
-            vae_latent_channels=latent_channels,
+            vae_latent_channels=self.latent_channels,
             do_normalize=False,
             do_binarize=True,
             do_convert_grayscale=True,
@@ -686,7 +686,10 @@ def prepare_latents(
             return latents.to(device=device, dtype=dtype), latent_image_ids
 
         image = image.to(device=device, dtype=dtype)
-        image_latents = self._encode_vae_image(image=image, generator=generator)
+        if image.shape[1] != self.latent_channels:
+            image_latents = self._encode_vae_image(image=image, generator=generator)
+        else:
+            image_latents = image
         if batch_size > image_latents.shape[0] and batch_size % image_latents.shape[0] == 0:
             # expand init_latents for batch_size
             additional_image_per_prompt = batch_size // image_latents.shape[0]