为头像添加圣诞帽（图像到图像）

以用户上传的参考图片为基础，为主体添加一顶经典的圣诞老人帽。

风格匹配：精确保留原始艺术风格（2D/3D/写实/动漫/卡通），保持身份、面部特征、发型、颜色、阴影和整体构图不变。

帽子设计：传统的圣诞老人帽（红色毛毡，带有细微的织物质感，白色蓬松边饰，白色绒球）。自然地放置在头部上方，与头部角度和发际线对齐。尊重透视、比例和头部形状。

整合：匹配现有的光照、阴影、高光、线条和渲染风格。在帽子接触头发/前额的地方添加逼真的接触阴影。不要改变面部、头发、背景、服装或任何其他元素。

输出：方形（1:1）头像，在小尺寸的个人资料图片下清晰锐利。

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**Original English:**
Using the user-uploaded reference image as the base, add a classic Christmas Santa hat to the subject.

Style match: preserve the original art style exactly (2D/3D/photorealistic/anime/cartoon), keeping identity, facial features, hairstyle, colors, shading, and overall composition unchanged.

Hat design: traditional Santa hat (red felt with subtle fabric texture, white fluffy trim, white pom-pom). Place it naturally on top of the head, aligned to head angle and hairline. Respect perspective, scale, and head shape.

Integration: match the existing lighting, shadows, highlights, linework, and rendering style. Add realistic contact shadows where the hat touches hair/forehead. Do not alter the face, hair, background, clothing, or any other elements.

Output: square (1:1) avatar, crisp and clear at small profile-picture size.