How I removed ~190MB of image files from my Git repo

gistfile1.txt

app/assets/images/exercises/**/*.

exercise*frame_*.jp{g,eg}
*_thumb.jp{g,eg}

1. Get list of unwanted files
$ git log --raw |awk '/^:/ { if (! printed[$6]) { print $6; printed[$6] = 1 }}'|while read f;do if [ ! -f $f ]; then echo Deleted: $f;fi;done 

SEE http://stackoverflow.com/questions/7336252/how-to-remove-all-files-in-a-git-repository-that-are-not-in-the-working-director/7399719#7399719

2. Use sed to remove ones that don't fit pattern

3. Get mirror of repo
`git clone --mirror git://example.com/some-big-repo.git`

3. Use repo cleaner
https://rtyley.github.io/bfg-repo-cleaner/

E.g., java -jar ~/Downloads/bfg-1.12.4.jar --delete-files "*_thumb.jp{g,eg}" some-big-repo.git

4. Push to new repo

5. Clone that repo

6. Add heroku remote

7. heroku:repo reset -a appname

8. Push your new repo to heroku