I'll add even another reason to replace Pillow with something else or at least make it optional, space (and network) optimization.

In a project we recently added the Jira package as a dependency, the Docker image grew a few MB and made me a bit curious how only one lib could add more than 10 MB.

Pillow (9.4 MiB) and PIL (6.4 MiB) are "heavy" dependencies in comparison with the Jira library (540 KiB). I know we're talking roughly 16 MB, but still, it adds up.

The PIL library is only being used in one line of code in the whole project, here [1] for guessing the mimetype of the avatar image.

[1]

To get a better picture I did a quick experiment using the python:3.11-alpine image and then installing jira and pillow libraries separatedly.

python               3.11-alpine          f5c01bd13f32   6 weeks ago         52.5MB
python-with-pillow   3.11-alpine          0df0d8893ede   3 minutes ago       84.9MB
python-with-jira     3.11-alpine          fc04344867e0   3 minutes ago       91.8MB

I estimate a "pillow-less" python-with-jira image could be around 60MB.

I would like to add another reason.

Using PIL/Pillow on AWS Lambda is kind of pain. I can't build my Application in the CI/CD Pipeline because AWS Lambda can't handle PIL/Pillow when build on Alpine. This is mainly because of the c libs used by PIL/Pillow.

Now there are just those solutions:

1. Using a special Container and build my application with aws sam cli (adding the container as another layer of potentially more hazzle)
2. Using a aws lambda compatible container on build time instead of the neat little alpine container. -> Conatiner is 6 times bigger than alpine

Both solutions are overhead, especially if you take into consideration that I simply don't need the PIL/Pillow functionality in the Jira Lib.

Pillow was added in #1680 because of this issue #1557
@ABizzinotto just have a look at this thread please.

I think Pillow is a way to complex and large dependency for the task in your MR.

I agree with others that pillow is a bit overkill for this situation. According to PEP 594 which removes the imghdr lib, the recommended replacements are filetype, puremagic, and python-magic.

Of these, python-magic requires libmagic which may cause issues for cross-platform support. puremagic and filetype look to be lightweight and not require any external dependencies. The example code in filetype looks like it may be a good drop in replacement for what imghdr was being used for. I would suggest going with filetype.