You can construct a matrix of RGB objects from Colors.jl and use Makie commands to plot like image:
https://docs.makie.org/v0.19.0/examples/plotting_functions/image/index.html
In MeshViz.jl we wrap some of these low-level functions into more high-level recipes for geospatial data:
You can watch my JuliaCon talk to get an idea of what is possible: