From 2cb97c3ceee9a18a54060c8a9d27cdc95e12c559 Mon Sep 17 00:00:00 2001
From: midzelis <min123@gmail.com>
Date: Fri, 5 Dec 2025 15:19:44 +0000
Subject: [PATCH] feat: PreloadManager

---
 .../assets/thumbnail/image-thumbnail.svelte   |  4 +-
 web/src/lib/managers/PreloadManager.svelte.ts | 37 +++++++++++++++++++
 web/src/lib/utils.ts                          | 36 +++++++++++++++++-
 3 files changed, 74 insertions(+), 3 deletions(-)
 create mode 100644 web/src/lib/managers/PreloadManager.svelte.ts

diff --git a/web/src/lib/components/assets/thumbnail/image-thumbnail.svelte b/web/src/lib/components/assets/thumbnail/image-thumbnail.svelte
index 2b55ea57b2..740cf784b7 100644
--- a/web/src/lib/components/assets/thumbnail/image-thumbnail.svelte
+++ b/web/src/lib/components/assets/thumbnail/image-thumbnail.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
   import BrokenAsset from '$lib/components/assets/broken-asset.svelte';
-  import { cancelImageUrl } from '$lib/utils/sw-messaging';
+  import { preloadManager } from '$lib/managers/PreloadManager.svelte';
   import { Icon } from '@immich/ui';
   import { mdiEyeOffOutline } from '@mdi/js';
   import type { ActionReturn } from 'svelte/action';
@@ -60,7 +60,7 @@
       onComplete?.(false);
     }
     return {
-      destroy: () => cancelImageUrl(url),
+      destroy: () => preloadManager.cancelPreloadUrl(url),
     };
   }
 
diff --git a/web/src/lib/managers/PreloadManager.svelte.ts b/web/src/lib/managers/PreloadManager.svelte.ts
new file mode 100644
index 0000000000..9074bd94b6
--- /dev/null
+++ b/web/src/lib/managers/PreloadManager.svelte.ts
@@ -0,0 +1,37 @@
+import { getAssetUrl } from '$lib/utils';
+import { cancelImageUrl, preloadImageUrl } from '$lib/utils/sw-messaging';
+import { AssetTypeEnum, type AssetResponseDto } from '@immich/sdk';
+
+class PreloadManager {
+  preload(asset: AssetResponseDto | undefined) {
+    if (!asset) {
+      return;
+    }
+    if (globalThis.isSecureContext) {
+      preloadImageUrl(getAssetUrl({ asset }));
+      return;
+    }
+    if (asset.type === AssetTypeEnum.Image) {
+      const img = new Image();
+      img.src = getAssetUrl({ asset });
+    }
+  }
+
+  cancel(asset: AssetResponseDto | undefined) {
+    if (!globalThis.isSecureContext || !asset) {
+      return;
+    }
+    const url = getAssetUrl({ asset });
+    cancelImageUrl(url);
+  }
+
+  cancelPreloadUrl(url: string) {
+    if (!globalThis.isSecureContext) {
+      return;
+    }
+
+    cancelImageUrl(url);
+  }
+}
+
+export const preloadManager = new PreloadManager();
diff --git a/web/src/lib/utils.ts b/web/src/lib/utils.ts
index 100f807273..285a8de491 100644
--- a/web/src/lib/utils.ts
+++ b/web/src/lib/utils.ts
@@ -1,10 +1,12 @@
 import { defaultLang, langs, locales } from '$lib/constants';
 import { authManager } from '$lib/managers/auth-manager.svelte';
-import { lang } from '$lib/stores/preferences.store';
+import { alwaysLoadOriginalFile, lang } from '$lib/stores/preferences.store';
+import { isWebCompatibleImage } from '$lib/utils/asset-utils';
 import { handleError } from '$lib/utils/handle-error';
 import {
   AssetJobName,
   AssetMediaSize,
+  AssetTypeEnum,
   MemoryType,
   QueueName,
   finishOAuth,
@@ -17,6 +19,7 @@ import {
   linkOAuthAccount,
   startOAuth,
   unlinkOAuthAccount,
+  type AssetResponseDto,
   type MemoryResponseDto,
   type PersonResponseDto,
   type ServerVersionResponseDto,
@@ -191,6 +194,37 @@ const createUrl = (path: string, parameters?: Record<string, unknown>) => {
 
 type AssetUrlOptions = { id: string; cacheKey?: string | null };
 
+export const getAssetUrl = ({
+  asset,
+  sharedLink,
+  forceOriginal = false,
+}: {
+  asset: AssetResponseDto;
+  sharedLink?: SharedLinkResponseDto;
+  forceOriginal?: boolean;
+}) => {
+  const id = asset.id;
+  const cacheKey = asset.thumbhash;
+  if (sharedLink && (!sharedLink.allowDownload || !sharedLink.showMetadata)) {
+    return getAssetThumbnailUrl({ id, size: AssetMediaSize.Preview, cacheKey });
+  }
+  const targetSize = targetImageSize(asset, forceOriginal);
+  return targetSize === 'original'
+    ? getAssetOriginalUrl({ id, cacheKey })
+    : getAssetThumbnailUrl({ id, size: targetSize, cacheKey });
+};
+
+const forceUseOriginal = (asset: AssetResponseDto) => {
+  return asset.type === AssetTypeEnum.Image && asset.duration && !asset.duration.includes('0:00:00.000');
+};
+
+export const targetImageSize = (asset: AssetResponseDto, forceOriginal: boolean) => {
+  if (forceOriginal || get(alwaysLoadOriginalFile) || forceUseOriginal(asset)) {
+    return isWebCompatibleImage(asset) ? 'original' : AssetMediaSize.Fullsize;
+  }
+  return AssetMediaSize.Preview;
+};
+
 export const getAssetOriginalUrl = (options: string | AssetUrlOptions) => {
   if (typeof options === 'string') {
     options = { id: options };