git-cleanup

git-pack-size.sh

# BEFORE
/tmp/git-cleanup/repo.git $ git count-objects -v 
count: 0
size: 0
in-pack: 204529
packs: 1
size-pack: 574968
prune-packable: 0
garbage: 0
size-garbage: 0

# AFTER
/tmp/git-cleanup/repo.git $ git count-objects -v 
count: 0
size: 0
in-pack: 201772
packs: 1
size-pack: 103437
prune-packable: 0
garbage: 0
size-garbage: 0

shrink-git.sh

# make sure you have java installed
mkdir /tmp/git-cleanup
cd /tmp/git-cleanup
wget http://repo1.maven.org/maven2/com/madgag/bfg/1.12.15/bfg-1.12.15.jar
alias bfg="java -jar bfg-1.12.15.jar "
git clone --mirror https://github.com/path_to/repo
cp -r repo.git repo.git.backup
cd repo.git
# create a list of objects you want to remove
git rev-list --objects --all | awk '/images_that_should_not_be.*(jpg|JPG)/ {print $1}' > ../images.txt
git count-objects -v
cd ..
# this does the removal. more details: https://rtyley.github.io/bfg-repo-cleaner/#usage 
bfg --delete-files '{comma_separated,globs*.bin}' --strip-blobs-with-ids images.txt repo.git
cd repo.git
git reflog expire --expire=now --all
git gc --prune=now --aggressive
# see git-pack-size.sh for example of before/after
git count-objects -v 

# WARNING: once you push, you are rewriting the history
# you willl want to coordinate this with teammates and
# have them delete their local repo and clone again once
# you push the 'lighter' repo
git push origin master