If a working image is all you want, then committing it is fine. You will then get a new image that includes your fix.

However, the benefit of having a Dockerfile is that your build is reproducible, so if your ever want to share the image with someone else, or foresee yourself rebuilding it, you should probably maintain the Dockerfile.

Basically you have two options:

• Fix your Dockerfile and rebuild it, that's the reason we have Dockerfile, from which an expected/correct image can be built by anybody at anywhere
• Run a container from your incorrect image and fix it, then commit back to the image. You can choose this option when your building process is extremely long but what you need is to do a quick/small fix. But remember to always fix Dockerfile, which is the "definetion" of your image and I believe you don't want to leave any kind of "bug" in it.