Image Compression Guide
Use the compression ratio calculator, then learn how lossy and lossless methods affect quality, formats, and web performance.
Measure image compression
Compare before and after file sizes to quantify savings and choose an appropriate workflow.
Make image compression measurable
Calculate actual savings
Compare original and compressed file sizes as a percentage and ratio.
Understand the method
Choose lossy or lossless compression based on content and reuse needs.
Check visual quality
Use the result as a guide, then inspect fine details at intended display size.
Lossy vs lossless compression
| Method | What changes | 最适合 | Typical formats |
|---|---|---|---|
| 有损 | Discards selected image detail | Photos and web delivery | JPG, WebP, AVIF |
| 无损 | Preserves decoded pixels | Graphics, text, editing | PNG, lossless WebP |
它是如何运作的
- 1
输入您的要求
提供文件大小或选择网站图像特征。
- 2
查看结果
阅读计算出的节省额或推荐的格式和理由。
- 3
下载决定
保存内容或优化工作流程的结果。
A practical image compression workflow
常见问题
What is image compression?
Image compression reduces storage and transfer size by encoding pixels more efficiently or discarding selected detail.
What is the difference between lossy and lossless?
Lossy compression removes some detail for smaller files; lossless compression preserves decoded image data.
What compression ratio is good?
There is no universal ratio. The right result is the smallest file that still looks acceptable at its intended size.
Image Compression Guide last reviewed: Jul 18, 2026.