diff --git a/nixos/modules/installer/cd-dvd/installation-cd-graphical-calamares-plasma6.nix b/nixos/modules/installer/cd-dvd/installation-cd-graphical-calamares-plasma6.nix
index f71a624156cd..90683fa088dc 100644
--- a/nixos/modules/installer/cd-dvd/installation-cd-graphical-calamares-plasma6.nix
+++ b/nixos/modules/installer/cd-dvd/installation-cd-graphical-calamares-plasma6.nix
@@ -24,6 +24,16 @@
     pkgs.maliit-keyboard
   ];
 
+  environment.plasma6.excludePackages = [
+    # Optional wallpapers that add 126 MiB to the graphical installer
+    # closure. They will still need to be downloaded when installing a
+    # Plasma system, though.
+    pkgs.kdePackages.plasma-workspace-wallpapers
+  ];
+
+  # Avoid bundling an entire MariaDB installation on the ISO.
+  programs.kde-pim.enable = false;
+
   system.activationScripts.installerDesktop =
     let
 
diff --git a/nixos/modules/services/desktop-managers/plasma6.nix b/nixos/modules/services/desktop-managers/plasma6.nix
index ef9c66d1336d..c70bb52966c0 100644
--- a/nixos/modules/services/desktop-managers/plasma6.nix
+++ b/nixos/modules/services/desktop-managers/plasma6.nix
@@ -136,7 +136,6 @@ in
           breeze-icons
           breeze-gtk
           ocean-sound-theme
-          plasma-workspace-wallpapers
           pkgs.hicolor-icon-theme # fallback icons
           qqc2-breeze-style
           qqc2-desktop-style
@@ -158,6 +157,7 @@ in
           [
             aurorae
             plasma-browser-integration
+            plasma-workspace-wallpapers
             konsole
             kwin-x11
             (lib.getBin qttools) # Expose qdbus in PATH