Stable Diffusion `img2img` Pipeline does not check image type

[tsunrise]

It would be better if img2img pipeline checks if the type of image is valid. Currently, this pipeline only supports tensor, PIL.Image, or a list of PIL.Image, but this type check is missing in https://github.com/huggingface/diffusers/blob/62608a9102e423ad0fe79f12a8ceb1710d2027b2/src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_img2img.py#LL378C10-L378C10

As a result, if the user gives incorrectly typed image (for example, an numpy array), some unhelpful message will appear such as

 File "path\to\diffusers\pipelines\stable_diffusion\pipeline_stable_diffusion_img2img.py", line 403, in prepare_latents
    image = image.to(device=device, dtype=dtype)
AttributeError: 'numpy.ndarray' object has no attribute 'to'

We can also add this check in

diffusers/src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_img2img.py

Line 45 in 62608a9

def preprocess(image):

as well.

[patrickvonplaten]

Thanks a lot for fixing this @Shubhamai , I think we can close this one now :-)