Images as Layered Snapshots: Docker images are built as layers - base image (foundation), working directory setup, source code copy, and execution commands - like constructing a building floor by floor
Base Images as Foundations: The FROM instruction pulls a preconfigured environment that serves as the foundation layer, similar to a building's foundation that everything else is built upon
Working Directory Intelligence: Containers automatically navigate to the specified WORKDIR when executing commands, eliminating the need to specify full paths in execution commands
Four-Layer Architecture: Every Dockerfile follows a pattern - base environment → working directory → source code → execution command - creating a complete, self-contained application package
Image vs Container Relationship: Images are static templates/snapshots, while containers are running instances created from those images that execute the predefined commands
Automatic Image Tagging: When no tag is specified during build, Docker automatically tags images as latest - explicit versioning (e.g., 0.0.1) is better for production environments
Dockerfile Context Awareness: The build context (represented by . in build commands) determines which files are available to copy into the image from the host machine
Docker Ignore Benefits: .dockerignore files prevent unnecessary files (like Dockerfiles themselves) from being copied into images, keeping containers clean and focused on application needs
Simplified Container Creation: Building custom images dramatically simplifies container creation commands compared to complex docker run commands with volume mounts and environment setup