diff --git a/README.md b/README.md
index 3bb2f72..13cecc0 100644
--- a/README.md
+++ b/README.md
@@ -169,8 +169,9 @@ Generate professional infographics with 20 layout types and 17 visual styles. An
 # Specify both
 /baoyu-infographic path/to/content.md --layout funnel --style corporate-memphis
 
-# With aspect ratio
+# With aspect ratio (named preset or custom W:H)
 /baoyu-infographic path/to/content.md --aspect portrait
+/baoyu-infographic path/to/content.md --aspect 3:4
 ```
 
 **Options**:
@@ -178,7 +179,7 @@ Generate professional infographics with 20 layout types and 17 visual styles. An
 |--------|-------------|
 | `--layout <name>` | Information layout (20 options) |
 | `--style <name>` | Visual style (17 options, default: craft-handmade) |
-| `--aspect <ratio>` | landscape (16:9), portrait (9:16), square (1:1) |
+| `--aspect <ratio>` | Named: landscape (16:9), portrait (9:16), square (1:1). Custom: any W:H ratio (e.g., 3:4, 4:3, 2.35:1) |
 | `--lang <code>` | Output language (en, zh, ja, etc.) |
 
 **Layouts** (information structure):
diff --git a/README.zh.md b/README.zh.md
index c1951a9..a32cc6c 100644
--- a/README.zh.md
+++ b/README.zh.md
@@ -169,8 +169,9 @@ clawhub install baoyu-markdown-to-html
 # 同时指定布局和风格
 /baoyu-infographic path/to/content.md --layout funnel --style corporate-memphis
 
-# 指定比例
+# 指定比例（预设名称或自定义 W:H）
 /baoyu-infographic path/to/content.md --aspect portrait
+/baoyu-infographic path/to/content.md --aspect 3:4
 ```
 
 **选项**：
@@ -178,7 +179,7 @@ clawhub install baoyu-markdown-to-html
 |------|------|
 | `--layout <name>` | 信息布局（20 种选项） |
 | `--style <name>` | 视觉风格（17 种选项，默认：craft-handmade） |
-| `--aspect <ratio>` | landscape (16:9)、portrait (9:16)、square (1:1) |
+| `--aspect <ratio>` | 预设：landscape (16:9)、portrait (9:16)、square (1:1)。自定义：任意 W:H 比例（如 3:4、4:3、2.35:1） |
 | `--lang <code>` | 输出语言（en、zh、ja 等） |
 
 **布局**（信息结构）：
diff --git a/skills/baoyu-infographic/SKILL.md b/skills/baoyu-infographic/SKILL.md
index 7024534..f5c47c8 100644
--- a/skills/baoyu-infographic/SKILL.md
+++ b/skills/baoyu-infographic/SKILL.md
@@ -17,6 +17,7 @@ Two dimensions: **layout** (information structure) × **style** (visual aestheti
 /baoyu-infographic path/to/content.md
 /baoyu-infographic path/to/content.md --layout hierarchical-layers --style technical-schematic
 /baoyu-infographic path/to/content.md --aspect portrait --lang zh
+/baoyu-infographic path/to/content.md --aspect 3:4
 /baoyu-infographic  # then paste content
 ```
 
@@ -26,7 +27,7 @@ Two dimensions: **layout** (information structure) × **style** (visual aestheti
 |--------|--------|
 | `--layout` | 21 options (see Layout Gallery), default: bento-grid |
 | `--style` | 20 options (see Style Gallery), default: craft-handmade |
-| `--aspect` | landscape (16:9), portrait (9:16), square (1:1) |
+| `--aspect` | Named: landscape (16:9), portrait (9:16), square (1:1). Custom: any W:H ratio (e.g., 3:4, 4:3, 2.35:1) |
 | `--lang` | en, zh, ja, etc. |
 
 ## Layout Gallery
@@ -220,7 +221,7 @@ Use **single AskUserQuestion call** with multiple questions to confirm all optio
 | Question | When | Options |
 |----------|------|---------|
 | **Combination** | Always | 3+ layout×style combos with rationale |
-| **Aspect** | Always | landscape (16:9), portrait (9:16), square (1:1) |
+| **Aspect** | Always | Named presets (landscape/portrait/square) or custom W:H ratio (e.g., 3:4, 4:3, 2.35:1) |
 | **Language** | Only if source ≠ user language | Language for text content |
 
 **Important**: Do NOT split into separate AskUserQuestion calls. Combine all applicable questions into one call.
@@ -236,6 +237,10 @@ Combine:
 4. Structured content from Step 2
 5. All text in confirmed language
 
+**Aspect ratio resolution** for `{{ASPECT_RATIO}}`:
+- Named presets → ratio string: landscape→`16:9`, portrait→`9:16`, square→`1:1`
+- Custom W:H ratios → use as-is (e.g., `3:4`, `4:3`, `2.35:1`)
+
 ### Step 6: Generate Image
 
 1. Select available image generation skill (ask user if multiple)