diff --git a/src/assets/starter-environment-assets.ts b/src/assets/starter-environment-assets.ts
new file mode 100644
index 00000000..c62b74ab
--- /dev/null
+++ b/src/assets/starter-environment-assets.ts
@@ -0,0 +1,279 @@
+import type { ProjectDocument } from "../document/scene-document";
+import {
+  areWorldBackgroundSettingsEqual,
+  cloneWorldSettings,
+  createDefaultWorldSettings,
+  createDefaultWorldTimeOfDaySettings,
+  DEFAULT_NIGHT_IMAGE_ENVIRONMENT_INTENSITY,
+  type WorldBackgroundSettings
+} from "../document/world-settings";
+
+import {
+  cloneProjectAssetRecord,
+  type ImageAssetRecord,
+  type ProjectAssetRecord
+} from "./project-assets";
+
+const STARTER_ENVIRONMENT_STORAGE_KEY_PREFIX = "starter-image:";
+const STARTER_ENVIRONMENT_DIRECTORY = "/starter-environments";
+const STARTER_ENVIRONMENT_WIDTH = 1024;
+const STARTER_ENVIRONMENT_HEIGHT = 512;
+const DEFAULT_DAY_ENVIRONMENT_INTENSITY = 0.85;
+
+export const STARTER_DAY_ENVIRONMENT_ASSET_ID =
+  "starter-image-winter-soccer-field-day" as const;
+export const STARTER_NIGHT_ENVIRONMENT_ASSET_ID =
+  "starter-image-snow-mountains-night" as const;
+
+interface StarterEnvironmentAssetDefinition {
+  asset: ImageAssetRecord;
+  folderName: string;
+}
+
+const STARTER_ENVIRONMENT_LIBRARY: readonly StarterEnvironmentAssetDefinition[] =
+  [
+    {
+      asset: {
+        id: STARTER_DAY_ENVIRONMENT_ASSET_ID,
+        kind: "image",
+        sourceName: "Starter Winter Soccer Field Day.hdr",
+        mimeType: "image/vnd.radiance",
+        storageKey: `${STARTER_ENVIRONMENT_STORAGE_KEY_PREFIX}${STARTER_DAY_ENVIRONMENT_ASSET_ID}`,
+        byteLength: 1_474_206,
+        metadata: {
+          kind: "image",
+          width: STARTER_ENVIRONMENT_WIDTH,
+          height: STARTER_ENVIRONMENT_HEIGHT,
+          hasAlpha: false,
+          warnings: []
+        }
+      },
+      folderName: "winter_soccer_field_day"
+    },
+    {
+      asset: {
+        id: "starter-image-sunset-open-sky",
+        kind: "image",
+        sourceName: "Starter Sunset Open Sky.hdr",
+        mimeType: "image/vnd.radiance",
+        storageKey: `${STARTER_ENVIRONMENT_STORAGE_KEY_PREFIX}starter-image-sunset-open-sky`,
+        byteLength: 551_007,
+        metadata: {
+          kind: "image",
+          width: STARTER_ENVIRONMENT_WIDTH,
+          height: STARTER_ENVIRONMENT_HEIGHT,
+          hasAlpha: false,
+          warnings: []
+        }
+      },
+      folderName: "sunset_open_sky"
+    },
+    {
+      asset: {
+        id: "starter-image-evening-blue-sky",
+        kind: "image",
+        sourceName: "Starter Evening Blue Sky.hdr",
+        mimeType: "image/vnd.radiance",
+        storageKey: `${STARTER_ENVIRONMENT_STORAGE_KEY_PREFIX}starter-image-evening-blue-sky`,
+        byteLength: 509_472,
+        metadata: {
+          kind: "image",
+          width: STARTER_ENVIRONMENT_WIDTH,
+          height: STARTER_ENVIRONMENT_HEIGHT,
+          hasAlpha: false,
+          warnings: []
+        }
+      },
+      folderName: "evening_blue_sky"
+    },
+    {
+      asset: {
+        id: STARTER_NIGHT_ENVIRONMENT_ASSET_ID,
+        kind: "image",
+        sourceName: "Starter Snow Mountains Night.hdr",
+        mimeType: "image/vnd.radiance",
+        storageKey: `${STARTER_ENVIRONMENT_STORAGE_KEY_PREFIX}${STARTER_NIGHT_ENVIRONMENT_ASSET_ID}`,
+        byteLength: 1_394_352,
+        metadata: {
+          kind: "image",
+          width: STARTER_ENVIRONMENT_WIDTH,
+          height: STARTER_ENVIRONMENT_HEIGHT,
+          hasAlpha: false,
+          warnings: []
+        }
+      },
+      folderName: "snow_mountains_night"
+    }
+  ] as const;
+
+function cloneStarterEnvironmentAsset(
+  definition: StarterEnvironmentAssetDefinition
+): ImageAssetRecord {
+  return cloneProjectAssetRecord(definition.asset) as ImageAssetRecord;
+}
+
+function cloneWorldBackground(background: WorldBackgroundSettings) {
+  if (background.mode === "image") {
+    return {
+      mode: "image" as const,
+      assetId: background.assetId,
+      environmentIntensity: background.environmentIntensity
+    };
+  }
+
+  if (background.mode === "solid") {
+    return {
+      mode: "solid" as const,
+      colorHex: background.colorHex
+    };
+  }
+
+  return {
+    mode: "verticalGradient" as const,
+    topColorHex: background.topColorHex,
+    bottomColorHex: background.bottomColorHex
+  };
+}
+
+function createStarterEnvironmentBackground(
+  assetId: string,
+  environmentIntensity: number
+) {
+  return {
+    mode: "image" as const,
+    assetId,
+    environmentIntensity
+  };
+}
+
+function isDefaultDayBackground(background: WorldBackgroundSettings): boolean {
+  return areWorldBackgroundSettingsEqual(
+    background,
+    createDefaultWorldSettings().background
+  );
+}
+
+function isDefaultNightBackground(background: WorldBackgroundSettings): boolean {
+  return areWorldBackgroundSettingsEqual(
+    background,
+    createDefaultWorldTimeOfDaySettings().night.background
+  );
+}
+
+export function createStarterEnvironmentAssetRegistry(): Record<
+  string,
+  ImageAssetRecord
+> {
+  return Object.fromEntries(
+    STARTER_ENVIRONMENT_LIBRARY.map((definition) => [
+      definition.asset.id,
+      cloneStarterEnvironmentAsset(definition)
+    ])
+  );
+}
+
+export function isStarterEnvironmentImageAsset(
+  asset: ProjectAssetRecord | ImageAssetRecord
+): asset is ImageAssetRecord {
+  return (
+    asset.kind === "image" &&
+    asset.storageKey.startsWith(STARTER_ENVIRONMENT_STORAGE_KEY_PREFIX)
+  );
+}
+
+function getStarterEnvironmentDefinitionById(assetId: string) {
+  return (
+    STARTER_ENVIRONMENT_LIBRARY.find((definition) => definition.asset.id === assetId) ??
+    null
+  );
+}
+
+function getStarterEnvironmentDefinition(asset: ImageAssetRecord) {
+  return getStarterEnvironmentDefinitionById(asset.id);
+}
+
+export function getStarterEnvironmentTextureUrl(
+  asset: ImageAssetRecord
+): string {
+  const definition = getStarterEnvironmentDefinition(asset);
+
+  if (definition === null) {
+    throw new Error(`Unknown starter environment image asset ${asset.id}.`);
+  }
+
+  return `${STARTER_ENVIRONMENT_DIRECTORY}/${definition.folderName}/environment.hdr`;
+}
+
+export function getStarterEnvironmentPreviewUrl(
+  asset: ImageAssetRecord
+): string {
+  const definition = getStarterEnvironmentDefinition(asset);
+
+  if (definition === null) {
+    throw new Error(`Unknown starter environment image asset ${asset.id}.`);
+  }
+
+  return `${STARTER_ENVIRONMENT_DIRECTORY}/${definition.folderName}/preview.jpg`;
+}
+
+export function mergeStarterEnvironmentAssets(
+  assets: Record<string, ProjectAssetRecord>
+): Record<string, ProjectAssetRecord> {
+  const mergedAssets: Record<string, ProjectAssetRecord> = {};
+
+  for (const definition of STARTER_ENVIRONMENT_LIBRARY) {
+    mergedAssets[definition.asset.id] = cloneStarterEnvironmentAsset(definition);
+  }
+
+  for (const [assetId, asset] of Object.entries(assets)) {
+    mergedAssets[assetId] = cloneProjectAssetRecord(asset);
+  }
+
+  return mergedAssets;
+}
+
+export function applyStarterEnvironmentAssetsToProjectDocument(
+  document: ProjectDocument
+): ProjectDocument {
+  const mergedAssets = mergeStarterEnvironmentAssets(document.assets);
+
+  const nextScenes = Object.fromEntries(
+    Object.entries(document.scenes).map(([sceneId, scene]) => {
+      const nextWorld = cloneWorldSettings(scene.world);
+
+      if (isDefaultDayBackground(nextWorld.background)) {
+        nextWorld.background = createStarterEnvironmentBackground(
+          STARTER_DAY_ENVIRONMENT_ASSET_ID,
+          DEFAULT_DAY_ENVIRONMENT_INTENSITY
+        );
+      } else {
+        nextWorld.background = cloneWorldBackground(nextWorld.background);
+      }
+
+      if (isDefaultNightBackground(nextWorld.timeOfDay.night.background)) {
+        nextWorld.timeOfDay.night.background = createStarterEnvironmentBackground(
+          STARTER_NIGHT_ENVIRONMENT_ASSET_ID,
+          DEFAULT_NIGHT_IMAGE_ENVIRONMENT_INTENSITY
+        );
+      } else {
+        nextWorld.timeOfDay.night.background = cloneWorldBackground(
+          nextWorld.timeOfDay.night.background
+        );
+      }
+
+      return [
+        sceneId,
+        {
+          ...scene,
+          world: nextWorld
+        }
+      ];
+    })
+  );
+
+  return {
+    ...document,
+    assets: mergedAssets,
+    scenes: nextScenes
+  };
+}