There are two kinds of meme sender in every chat. One sends an image with a white rectangle around it, like a polaroid taped to the screen. The other sends a face, a shrug, a tiny dancing figure that floats over any background like it was born inside the app. The difference is not artistic talent — it is one technical trick: a transparent PNG, cut out cleanly and exported at the size the platform expects. This guide explains how the cutout actually works, what numbers Discord and WhatsApp demand, and how to do it all without uploading your photos anywhere.
每个群里都有两种发表情的人。一种发的图带着一个白色矩形框，像把拍立得贴在屏幕上。另一种发的是一张脸、一个耸肩、一个跳舞的小人，悬浮在任何背景之上，仿佛天生就长在 App 里。差别不在艺术天赋——而在一个技术小技巧：一张干净抠图、按平台尺寸导出的透明 PNG。本指南讲清楚抠图到底怎么回事、Discord 和 WhatsApp 要求哪些数字，以及如何全程不上传照片地完成它。
What a transparent sticker actually is透明贴纸到底是什么
Every image file stores color, but only some formats store a fourth number per pixel: the alpha channel, which says how transparent that pixel is. A JPEG has no alpha channel at all — every pixel is forced fully opaque, which is why a JPEG "cutout" always comes back with a white box. A PNG can store 256 levels of transparency per pixel, so edges can fade out smoothly. When Discord or WhatsApp renders your sticker, it composites those semi-transparent pixels over the chat background, and that is the floating effect you see. If your export is a JPEG, no amount of good cutting matters — the white box comes back.
每个图片文件都存储颜色，但只有部分格式为每个像素多存一个数字：Alpha 通道，它表示这个像素有多透明。JPEG 完全没有 Alpha 通道——每个像素都被迫完全不透明，这就是为什么 JPEG「抠图」永远会带白框。PNG 可以为每个像素存储 256 级透明度，因此边缘可以平滑淡出。当 Discord 或 WhatsApp 渲染你的贴纸时，它把这些半透明像素合成到聊天背景之上——这就是你看到的悬浮效果。如果导出的是 JPEG，抠得再好也没用，白框一定会回来。
How the cutout works (the principle behind the button)抠图是怎么做到的（按钮背后的原理）
Background removal tools do one of two things. The simpler method is color-based flood fill: you click the background, the tool selects that color, and expands the selection through every connected pixel within a tolerance range until the whole background is gone. This works beautifully when the background is one solid color — a green screen, a white wall, a blue void. The harder method is edge-based (or model-based) segmentation: the tool looks for the boundary between a foreground subject and whatever surrounds it, using contrast, texture and learned object recognition. This is what lets it cut out a person from a messy room or a cat from grass.
抠图工具做的是两件事之一。简单的一种是基于颜色的 flood fill（漫水填充）：你点一下背景，工具选中那个颜色，然后在容差范围内向所有相连的像素扩展选区，直到整个背景消失。当背景是单一纯色时——绿幕、白墙、蓝色虚空——这个方法效果极好。更难的一种是基于边缘（或模型）的分割：工具寻找前景主体与周围环境之间的边界，利用对比度、纹理和训练好的物体识别模型。这就是它能把人从杂乱房间里、把猫从草地里抠出来的原理。
- Tolerance controls how forgiving color selection is. Too low and the sky remains in patches; too high and it bites into the subject's hair.
- 容差控制颜色选择的宽容度。太低，天空会一块一块留着；太高，就会咬进人物的头发里。
- Hair and fur are the famous failure case: fine strands are thinner than a pixel. Good tools feather the edge so strands blend; cheap tools leave a hard halo of the old background.
- 头发和毛发是著名的翻车区：细发丝比一个像素还细。好工具会羽化边缘让发丝自然过渡；差工具会留下一圈旧背景色的硬光晕。
- Refine in steps: cut first, then clean the edge. Trying to fix halo and stray pixels in one pass is why beginners get frustrated.
- 分步修：先抠图，再修边。想一遍过同时搞定光晕和杂边，就是新手抓狂的原因。
The exact size and format specs精确尺寸与格式规格
Each platform bakes in its own expectations. Build to the smallest common denominator and your sticker works everywhere:
每个平台都有自己的既定期待。按最小公约数来做，你的贴纸到处都能用：
- Discord: official sticker assets are 320×320 px max, transparent PNG, under 512 KB. Animated stickers may use WebM or GIF, but static PNG is what 99% of people want. Note that regular chat uploads top out at 8 MB per file, but stickers themselves are tiny — 320×320 keeps you well under every limit.
- Discord：官方贴纸资产最大 320×320px，透明 PNG，小于 512KB。动态贴纸可用 WebM 或 GIF，但 99% 的人想要的是静态 PNG。注意普通聊天上传上限是每文件 8MB，而贴纸本身很小——320×320 远低于所有限制。
- WhatsApp: stickers must be 512×512 px transparent PNGs under 100 KB, with the artwork centered in the square. You also need a 96×96 tray icon for the sticker pack shelf. The 100 KB cap is real — simplify the background removal and export without metadata bloat.
- WhatsApp：贴纸必须是 512×512px 透明 PNG，小于 100KB，画面居中。贴纸包货架还需要一个 96×96 的托盘图标。100KB 上限是真实的——精简抠图结果，导出时去掉多余元数据。
- Telegram (bonus): 512×512, WEBP or WEBP-animated; PNG also previews fine in chat.
- Telegram（附赠）：512×512，WEBP 或动态 WEBP；PNG 在聊天里预览也没问题。
Your five-step sticker workflow五步贴纸工作流
- Pick a source with a clean background. A face on a flat wall cuts in seconds; a full-body shot in a forest will need cleanup. Start with the easiest photo you can.
- 选背景干净的素材。平墙上的脸几秒钟就抠好；森林里的全身照需要修边。从最容易的那张照片开始。
- Run the cutout. In our Transparent Sticker Maker, drop the photo in and the background is removed automatically, right on your device.
- 执行抠图。在我们的透明贴纸制作器里拖入照片，背景会在你的设备上自动去除。
- Crop to the subject. Trim empty transparent space so the face or figure fills about 80% of the frame — stickers shrink to thumbnails, so dead space is wasted pixels.
- 裁到主体。裁掉多余的透明区域，让脸或人物填满画面约 80%——贴纸会缩小成缩略图，留白就是浪费像素。
- Scale to the target size. 320×320 for Discord, 512×512 for WhatsApp. Design once at 512 and downscale copies for Discord; never upscale.
- 缩放到目标尺寸。Discord 用 320×320，WhatsApp 用 512×512。按 512 做一版，缩小出 Discord 用的副本；永远不要放大。
- Export as PNG. Check the preview against a dark background — if a halo appears, lower the edge tolerance or add a 1–2 px outline, which also makes stickers read better at tiny sizes.
- 导出 PNG。把预览放到深色背景上检查——如果出现光晕，降低边缘容差，或加 1–2px 描边，描边还能让贴纸在极小尺寸下更清晰。
The privacy question people skip大家都跳过的隐私问题
Most online cutout tools send your photo to a server, run an AI model there, and hand the result back. That is usually fine for a meme of your cat. It is not fine when the photo contains your face, your ID, your coworkers, or anything from a work machine. Our cutout runs locally in your browser with Canvas and image-processing code — the photo you drop in never leaves your device, which is exactly why we built it. A quick rule: if the tool asks you to sign in before cutting, it is almost certainly keeping a copy somewhere. For more on how we handle images, read our Privacy Policy.
大多数在线抠图工具会把你的照片传到服务器、在服务器上跑 AI 模型、再把结果发回来。拿猫的表情包这么做通常没事。但当照片里有你的脸、你的证件、你的同事、或者来自工作电脑时，就不行了。我们的抠图在你的浏览器里本地运行，用的是 Canvas 和图像处理代码——你拖进去的照片永远不会离开你的设备，这正是我们做这个工具的原因。一个快速判断法：如果工具要求你先登录才能抠图，它几乎肯定在某个地方留了副本。关于我们如何处理图片，详见隐私政策。
FAQ常见问题
What file type do transparent stickers need to be?透明贴纸需要什么文件格式？
A PNG with an alpha channel. PNG is the common web format that stores partial transparency, so edges fade out smoothly instead of cutting into a hard square.
带 Alpha 通道的 PNG。PNG 是唯一能存储半透明的常见网络格式，边缘可以平滑淡出，而不是硬切成方块。
What size should my Discord sticker be?Discord 贴纸该做多大？
Discord sticker assets should be 320×320 px at most, under 512 KB, as a transparent PNG. In chat, any transparent PNG works as a reaction; 320×320 is what the official sticker format expects.
Discord 贴纸资产最大 320×320px，小于 512KB，透明 PNG。聊天里任何透明 PNG 都能当反应图用；320×320 才是官方贴纸格式要求的尺寸。
What are WhatsApp sticker requirements?WhatsApp 贴纸要求是什么？
Each sticker must be a 512×512 px transparent PNG under 100 KB, plus a 96×96 tray icon. Keep the subject inside the central area so it is not cramped.
每张贴纸必须是 512×512px 透明 PNG，小于 100KB，外加一个 96×96 的托盘图标。主体放在中央区域，不要顶边。
Why is there a white box around my sticker?为什么贴纸周围有白框？
The export was saved as JPEG, which has no transparency. JPEG fills transparent areas with white. Re-export as PNG and the box disappears.
导出存成了 JPEG，而 JPEG 没有透明度。JPEG 会把透明区域填成白色。重新导出为 PNG，白框就消失了。
Is it safe to upload my photos to a sticker maker?把照片上传到贴纸工具安全吗？
It depends. Our Transparent Sticker Maker runs entirely in your browser and your photo never leaves the device. Web tools that upload images to a server should be checked against their privacy policy before you use personal photos.
视情况而定。我们的透明贴纸制作器完全在你的浏览器里运行，照片从不离开设备。会把图片上传到服务器的网页工具，在使用私人照片之前请先查它的隐私政策。
