diff --git a/skills/baoyu-image-gen/scripts/providers/dashscope.ts b/skills/baoyu-image-gen/scripts/providers/dashscope.ts
index 607a947..e59a048 100644
--- a/skills/baoyu-image-gen/scripts/providers/dashscope.ts
+++ b/skills/baoyu-image-gen/scripts/providers/dashscope.ts
@@ -22,27 +22,53 @@ function parseAspectRatio(ar: string): { width: number; height: number } | null
   return { width: w, height: h };
 }
 
-function getSizeFromAspectRatio(ar: string | null, quality: CliArgs["quality"]): string {
-  const baseSize = quality === "2k" ? 1440 : 1024;
+const STANDARD_SIZES: [number, number][] = [
+  [1024, 1024],
+  [1280, 720],
+  [720, 1280],
+  [1024, 768],
+  [768, 1024],
+  [1536, 1024],
+  [1024, 1536],
+  [1536, 864],
+  [864, 1536],
+];
 
-  if (!ar) return `${baseSize}*${baseSize}`;
+const STANDARD_SIZES_2K: [number, number][] = [
+  [1536, 1536],
+  [2048, 1152],
+  [1152, 2048],
+  [1536, 1024],
+  [1024, 1536],
+  [1536, 864],
+  [864, 1536],
+  [2048, 2048],
+];
+
+function getSizeFromAspectRatio(ar: string | null, quality: CliArgs["quality"]): string {
+  const is2k = quality === "2k";
+  const defaultSize = is2k ? "1536*1536" : "1024*1024";
+
+  if (!ar) return defaultSize;
 
   const parsed = parseAspectRatio(ar);
-  if (!parsed) return `${baseSize}*${baseSize}`;
+  if (!parsed) return defaultSize;
 
-  const ratio = parsed.width / parsed.height;
+  const targetRatio = parsed.width / parsed.height;
+  const sizes = is2k ? STANDARD_SIZES_2K : STANDARD_SIZES;
 
-  if (Math.abs(ratio - 1) < 0.1) {
-    return `${baseSize}*${baseSize}`;
+  let best = defaultSize;
+  let bestDiff = Infinity;
+
+  for (const [w, h] of sizes) {
+    const diff = Math.abs(w / h - targetRatio);
+    if (diff < bestDiff) {
+      bestDiff = diff;
+      best = `${w}*${h}`;
+    }
   }
 
-  if (ratio > 1) {
-    const w = Math.round(baseSize * ratio);
-    return `${w}*${baseSize}`;
-  }
-
-  const h = Math.round(baseSize / ratio);
-  return `${baseSize}*${h}`;
+  return best;
 }
 
 function normalizeSize(size: string): string {