fix bug causing a warning message in Acrobat

[GerardoAllende]

Fixes #960 #1144

Checklist:

• The GitHub pipeline is OK (green)

• A unit test is covering the code added / modified by this PR
  Not necessary in this case IMHO

• This PR is ready to be merged

• In case of a new feature, docstrings have been added, with also some documentation in the docs/ folder

• A mention of the change is present in CHANGELOG.md

By submitting this pull request, I confirm that my contribution is made under the terms of the GNU LGPL 3.0 license.

[andersonhc]

There are 2 tests failing:
2024-04-11T21:43:38.8306068Z test/image/image_types/test_insert_images.py::test_insert_jpg_jpxdecode FAILED [ 37%]
2024-04-11T21:43:39.9141525Z test/image/png_indexed/test_png_indexed.py::test_png_indexed_no_transparency FAILED [

[GerardoAllende]

Strange, they are not failing on my machine...

I'll investigate

[gmischler]

Cool piece of investigation, figuring this out. Thanks!

[gmischler]

There are 2 tests failing:

Where do you see that?
Edit: Oh, now I see the two changed files.

[andersonhc]

@allcontributors
please add @GerardoAllende for bug.
please add @GerardoAllende for research.

[allcontributors]

@andersonhc

I've put up a pull request to add @GerardoAllende! 🎉