Image column is not decoded in map when using with with_transform
COLLABORATOR
Hi! This behavior stems from this line: https://github.com/huggingface/datasets/blob/799b817d97590ddc97cbd38d07469403e030de8c/src/datasets/arrow_dataset.py#L1919
Basically, the `Image`/`Audio` columns are decoded only if the `format_type` attribute is `None` (`set_format`/`with_format` and `set_transform`/`with_transform` assign a non-`None` value to it) and the  `input_columns` param is not specified (see https://github.com/huggingface/datasets/issues/3756). We will remove these limitations soon.




2022-03-23T15:47:10Z
https://github.com/huggingface/datasets/issues/3992#issuecomment-1076502728
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2022-03-23T15:47:10Z
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## Describe the bug
Image column is not _decoded_ in **map** when using with `with_transform`

## Steps to reproduce the bug
```python
from datasets import Image, Dataset

def add_C(batch):
    batch["C"] = batch["A"]
    return batch

ds = Dataset.from_dict({"A": ["image.png"]}).cast_column("A",  Image())
ds = ds.with_transform(lambda x: x)  # <= This line causes the problem
ds = ds.map(add_C, batched=True)
print(ds[0])
```

## Expected results
```
{'C': <PIL.PngImagePlugin.PngImageFile>,  ...}
```

## Actual results
```
{'C': {'bytes': None, 'path': 'image.png'}, ...}
```

If we remove the `with_transform` line, we get the expected result.

## Environment info
- `datasets` version: 2.0.0
- Platform: Mac OSX
- Python version: 3.8.12
- PyArrow version: 7.0.0
