How to do a clean install of python from source in a Docker container? (Image gets very large)

Currently I have to create Docker images that build python from source (for example we do need two different python versions in a container, one python version for building and one for testing the application, also we need to exactly specify the python version we want to install and newer versions are not supported via apt install for example).

My Problem is a.t.m. that the size of the image gets really large if you build python from source and yet I do not fully understand why.

Let’s take the following image as an example:

# we start with prebuild python image to set system python to 3.13
FROM WWW.SOMEURL.COM/python:3.13-slim-bullseye  

# now we install the build dependencies required to build python from source
RUN apt update -y &&
    apt upgrade -y &&
    apt-get install --no-install-recommends --yes 
        build-essential 
        zlib1g-dev 
        libncurses5-dev 
        libgdbm-dev 
        libnss3-dev 
        libssl-dev 
        libreadline-dev 
        libffi-dev 
        libsqlite3-dev 
        libbz2-dev 
        git 
        wget &&
    apt-get clean

# next we altinstall another python version by building it from source
RUN   cd /usr/src &&
      wget "https://www.python.org/ftp/python/3.11.11/Python-3.11.11.tgz" &&
      tar xzf "Python-3.11.11.tgz" &&
      cd "Python-3.11.11" &&
      ./configure &&
      make altinstall

# finally we remove the build dependencies to safe some space
RUN apt-get remove --purge  -y 
        build-essential 
        zlib1g-dev 
        libncurses5-dev 
        libgdbm-dev 
        libnss3-dev 
        libssl-dev 
        libreadline-dev 
        libffi-dev 
        libsqlite3-dev 
        libbz2-dev 
        git 
        wget &&
    apt-get autoremove --purge -y &&
    apt-get autoclean -y

# verify installation
RUN echo "DEBUG: Path to alt python: $(which python3.11) which has version $(python3.11 --version)"

For me this process results in a very large image, while the python installation itself should not be that large (~150-200 MB on a local machine). However, it seems like the pure installation of python from source adds around 800MB to the image. Why is this the case?

Thank you for your help!