diff --git a/Precompile.jl b/deps/precompile.jl
similarity index 94%
rename from Precompile.jl
rename to deps/precompile.jl
index e4f84ac30..efe6fb867 100644
--- a/Precompile.jl
+++ b/deps/precompile.jl
@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE
 
-using OpticSim
+using OpticSim # this will only work after the main build steps are completed
 @info "Running representative workload"
 # add stuff here #
 Examples.autodrawrays()
diff --git a/src/Sysimage.jl b/deps/sysimage.jl
similarity index 91%
rename from src/Sysimage.jl
rename to deps/sysimage.jl
index 52301602b..6b7a6136e 100644
--- a/src/Sysimage.jl
+++ b/deps/sysimage.jl
@@ -20,17 +20,16 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE
 
-module Sysimage
 import Pkg, Libdl, PackageCompiler
 
 function compile(sysimage_path = "JuliaSysimage.$(Libdl.dlext)")
     env_to_precompile = joinpath(@__DIR__, "..")
-    precompile_execution_file = joinpath(env_to_precompile, "Precompile.jl")
+    precompile_execution_file = joinpath(@__DIR__, "precompile.jl")
     project_filename = joinpath(env_to_precompile, "Project.toml")
     project = Pkg.API.read_project(project_filename)
     used_packages = Symbol.(collect(keys(project.deps)))
     # don't need these ever after building this so no need to have them in the sysimage
-    used_packages = filter(x -> x ∉ [:Libdl, :PackageCompiler, :Pkg], used_packages)
+    filter!(x -> x ∉ [:Libdl, :PackageCompiler, :Pkg], used_packages)
     if Libdl.dlext == "dll"
         @warn "Ignoring packages which use gl dlls on Windows as these cause build errors"
         # see https://github.com/JuliaLang/PackageCompiler.jl/issues/365
@@ -40,5 +39,3 @@ function compile(sysimage_path = "JuliaSysimage.$(Libdl.dlext)")
     @info "Building a custom sysimage for OpticSim.jl."
     PackageCompiler.create_sysimage(used_packages, sysimage_path = sysimage_path, project = env_to_precompile, precompile_execution_file = precompile_execution_file)
 end
-
-end # module Sysimage
diff --git a/src/OpticSim.jl b/src/OpticSim.jl
index 8002bb4d6..d2aa0ab7d 100644
--- a/src/OpticSim.jl
+++ b/src/OpticSim.jl
@@ -45,8 +45,6 @@ include("Visualization.jl")
 include("Examples.jl")
 include("Optimization/Optimizable.jl")
 
-include("Sysimage.jl")
-
 ################################################
 
 # This can be used to track NaN, particularly in ForwardDiff gradients, causing problems