Seed Image with Project Partially Installed

[seandenigris]

I have a few projects that are largely consist of one primary dependent project. To save CI time (which is limited for private GH projects), I was thinking of using the build artifact from the dependency as the base image in which to complete the installation. I noticed SmalltalkCI has an -i flag to supply an image, which seems like what I need.

Is the plan above feasible? If so, is there an example of how to go about it? If not, any pointers?