Container image size is crucial in cloud native app development. Bloated images slow down deployment pipelines, increase attack surfaces and inflate costs. This is a major problem across most tech organisations. This session dives deep into the art of container image reduction, exploring various techniques and tools that help achieve this. We’ll begin with an overview of overlay filesystems, explaining how they work and understanding their role in building container images. This will be followed by a deep dive into inspecting container images layer by layer and analyzing Dockerfiles, with a focus on best practices for writing lean and efficient Dockerfiles and common pitfalls to avoid. We’ll then move on to leveraging open-source tools and techniques to reduce container image sizes, demonstrating the use of tools like dive, docker-squash, and stargz-snapshotter, as well as techniques such as multi-stage builds, to significantly reduce container image sizes by over 80%, which is critical in production scenarios. The workshop/talk will be highly interactive, featuring audience quizzes throughout to reinforce learning and ensure engagement. By the end of this session, attendees will have a solid understanding of how to reduce their container image sizes, making their cloud-native applications faster, more secure, and more cost-effective. The session will conclude with a Q&A segment to address any remaining questions.