Last updated: 29 August 2026
支持 JPG、PNG 和 WebP 的免费在线图像压缩器
无需将照片发送到远程服务器即可在线压缩图片。这款免费工具可直接在浏览器中缩小 JPG/JPEG、PNG 和 WebP 文件。适用于表单限制、邮件附件过大或网站上传限制等场景。
AllFileCompressor 在本地处理所有文件。您的原图仍保留在设备上，同时方便您分享或发布更小体积的图片。
如何在线压缩图片
简单 4 步完成压缩：
- 拖放或选择 JPG、PNG 或 WebP 图片。
- 选择模式：智能（均衡）、极限（体积最小）或低压缩（画质最佳）。
- 开始压缩，处理过程在浏览器本地完成。
- 在预览中对比效果并下载压缩后的图片。
- Download the file, or compress another image.
Which Compression Mode Should You Use?
This image compressor exposes three quality presets. Use the table to pick a starting point, then trust the on-page size preview — every photo behaves differently. Start with Smart for most jobs; switch to Extreme only when a destination still rejects the file; use Low Compression when the preview looks soft.
| Mode | Typical size reduction | Best for |
|---|---|---|
| Smart Compress | Balanced cut (quality ~0.8; often a clear drop without looking “crushed”) | Everyday photos, CMS uploads, email, general web use |
| Extreme | Strongest cut (quality ~0.42; usually the smallest file of the three) | Strict caps, messaging apps, forms with tiny photo limits |
| Low Compression | Modest cut (quality ~0.92; prioritizes visual fidelity over maximum shrink) | Portfolios, product detail shots, when artifacts worry you |
Method note: figures describe the built-in quality presets in our browser pipeline (Smart / Extreme / Low), not a single universal %. Always compare KB in the preview after you run this photo compressor.
How Small Does Your Image Need to Be?
People search for ways to reduce image file size because a destination blocked them. Use these practical targets as a starting point, then re-check the live limit on the site you upload to. Mapping real upload limits beats generic advice like "make it smaller for the web."
| Where you are uploading | Practical target size | Suggested mode |
|---|---|---|
| Email attachments (e.g. Gmail total message cap) | Keep images well under ~5–10 MB each when several files share a 25 MB message | Smart; Extreme if still too heavy |
| CMS / WordPress-style media uploads | Often 2 MB default on shared hosting (host-dependent) | Smart first |
| Messaging apps (chat photo shares) | Aim under ~1–2 MB for smoother sends; apps may recompress anyway | Extreme when sends fail |
| Job / visa / exam application photo fields | Commonly 50–200 KB (read the form — rules vary) | Extreme, then resize if still over |
| Marketplace / product listing photos | Often 1–5 MB per image or a platform max | Smart for catalog shots |
| Website performance / page load budget | Hero images often aim for a few hundred KB when possible | Smart or Extreme |
Last checked: 29 August 2026. Upload caps change by provider and plan — verify before you publish. Review cadence: quarterly.
支持的格式
本工具针对最常用的网页图片格式进行了优化。
压缩 PNG
优化带有透明背景的截图和 UI 图形，提升加载速度。
How Image Compression Reduces File Size
Image compression removes redundant visual information and can simplify colour or strip bulk you do not need for display. In plain terms: lossy modes discard some detail for smaller files; lossless-style paths keep pixels intact but pack the file more tightly when the format allows.
| Type | What it means | Use when |
|---|---|---|
| Lossy compression | Throws away some visual detail (and often metadata) so the file gets smaller. Quality sliders and Extreme mode lean this way. | Photos, social, email, most web images where a tiny quality trade is fine |
| Lossless compression | Keeps pixel values the same while packing data more efficiently. Colour quantization and metadata stripping can still shrink files without a classic “blurry JPEG” look when used carefully. | UI assets, graphics with sharp edges, when you must preserve exact pixels |
Colour quantization reduces the number of distinct colours; metadata stripping drops camera tags you rarely need online. Some files are already optimized and will not shrink further in a meaningful way — we keep that honest result instead of pretending. Together, those techniques are how an image size reducer turns megabytes into kilobytes without always needing a desktop app.
More on image optimization for web: how to optimize images for the web.
为什么要减小图片体积？
优化文件体积有助于：
- 满足网站和 CMS 的上传大小限制
- 加快网页加载速度，提升用户体验
- 节省手机或云盘的存储空间
- 更轻松地通过邮件或即时通讯软件分享
优化后的图片是确保网页流畅运行和高效分享的关键。
浏览器端安全处理
我们利用 WebAssembly 技术确保文件处理在本地完成。您的隐私是我们的首要任务。
Verify it yourself
- Open DevTools → Network, compress an image, and confirm you do not see the photo file posted to our servers.
- Or turn on airplane mode / disconnect Wi‑Fi and compress anyway — local processing still works.
Read more on why zero-upload compression matters · Security & compliance.
Free and Pro Limits
Free plan: 5 successful uses of this image tool every 24 hours (auto-reset). Pro is $3/month for unlimited compressions and conversions with priority speed. Limits apply per tool, so image compressions do not consume your PDF or video free uses. See pricing.
Written with the AllFileCompressor engineering team — browser-based image compression pipeline (Canvas / Web APIs).