[PORT-Hilserl] classifier fixes

[ChorntonYoel]

What this does

THis PR fixes the splitting of the reward classifier as well as the logging of images.
Examples:

Title	Label
Fixes #[issue]	(🐛 Bug)
Adds new dataset	(🗃️ Dataset)
Optimizes something	(⚡️ Performance)

How it was tested

Explain/show how you tested your changes.

Examples:

• Added test_something in tests/test_stuff.py.
• Added new_feature and checked that training converges with policy X on dataset/environment Y.
• Optimized some_function, it now runs X times faster than previously.

How to checkout & try? (for the reviewer)

Provide a simple way for the reviewer to try out your changes.

Examples:

pytest -sx tests/test_stuff.py::test_something

python lerobot/scripts/train.py --some.option=true

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