This is what Docker volumes are for: http://docs.docker.io/en/latest/use/working_with_volumes/
Be sure to have a look at other concepts in the documentation as well. There is some great stuff there ;)
Pregunta
I have an assets folder in the environment where pictures are uploaded, is there a way to copy this folder and import it after the image has compiled?
Or can I somehow use a folder outside of the image instead?
Solución
This is what Docker volumes are for: http://docs.docker.io/en/latest/use/working_with_volumes/
Be sure to have a look at other concepts in the documentation as well. There is some great stuff there ;)