Static output image size distorts executed output images

[aeisenbarth]

Describe the bug

When you have notebooks that are not executed ("execution_mode": "off") and notebooks that are executed, following images can be distorted.

This happens when the executor that was used for the static notebook has saved the size of embedded images:

{
 "data": {
  "image/png": "..."
  "text/plain": [
   "<IPython.core.display.Image object>"
  ]
 },
 "metadata": {
  "image/png": {
   "height": 100,
   "width": 500
  }
 },
 "output_type": "display_data"
}

The image size persists onto all following notebooks or cells that are executed by MyST-NB. This does not happen with jupyter lab or nbsphinx.

Reproduce the bug

1. Extract the attached docs.zip folder or create a conf.py:

   exclude_patterns = ["_build", "jupyter_execute"]
   extensions = ["myst_nb"]

   and an index.md:

   ```{toctree}
   example <example.ipynb>

   
   and the attached notebook file.

2. Build documentation: sphinx-build -b html docs docs/_build

3. You might see something like this:

   

List your environment

(The Github template contains a mistake in the environment command, this project is not jupyter-book, but myst-nb.)

$ pip freeze | grep -E "myst-nb|Sphinx"
myst-nb==1.1.0
Sphinx==7.2.6

[aeisenbarth]

Without having looked at the code, I think it could be a static class variable that should be an instance variable.