So, I have created a system image using PackageCompiler.jl with Plots. When I start julia with this system image, it cannot find the Plots package unless I also add Plots to my project environment. I thought the package should be “compiled-in”? Or is that not done by design?
I think making a system image will just make sure that the packages are already precompiled, not that they are added to any environment in your depot path. The reason that stdlibs and base are not needed to be in your project is probably because they are treated special in some other way.
You could make it work like this if you want, by creating a system image specific project and adding it somewhere in your depot path, but that could then be confusing if you ever want to share the code with others.