• enable you to login into multiple private registries at the same time
• which helps you building images which derive from image 1 form private registry A and pushing image 2 to registry B
• avoids using docker save/load at all costs, since both are very slow and blocking - push / pull is a lot faster
• cache is allow to fail and not exist, does not block the pipeline

Dockerfile can be found at https://github.com/EugenMayer/docker-image-resource-ng/tree/develop