Some of my pictures on Flickr, resized to < 100 KB to fit GitHub Arctic Code Vault filesize limit.
My pictures are CC-BY-SA licensed.
Useful command to resize all pictures in a directory:
find . -maxdepth 1 -iname "*.jpg" | xargs -L1 -I{} convert -define jpeg:extent=90kb "{}" "{}"
Be careful, it overwrites files.