Image Compressor

選擇壓縮等級

點擊或拖拽添加圖片

支援 PNG、JPG、JPEG、WEBP、GIF、AVIF、BMP、ICO、HEIC、JXL、TIFF，單張須小於 20MB，單次最多 10 張

Compress JPG, PNG, WEBP, GIF and more online with 3 quality levels. Batch processing supported, files auto-deleted after 2 hours for privacy.

Related

Image Converter

Image Resizer

Round Image Corners

Image Rotate & Flip

Compress PDF

Image to ASCII Art

What is image compression?

Image compression is a technique that reduces image file size through algorithms, divided into two types: lossy and lossless. Lossy compression (e.g., JPG, WEBP) significantly reduces file size by discarding data insensitive to the human eye (primarily high-frequency chrominance information), with virtually no visible difference at reasonable quality parameters. Lossless compression (e.g., PNG) reduces file size by optimizing data encoding without losing any image quality, but compression ratios are limited.

**Why is image compression important?** Unoptimized images on web pages often account for over 50% of total page traffic. LCP (Largest Contentful Paint) in Google's Core Web Vitals is directly affected by image loading speed; compressing images can significantly improve page load speed and SEO rankings. For scenarios like email attachments, form uploads, and social media publishing, image compression helps avoid exceeding file size limits.

**Choosing between three compression levels:** Recommended compression (quality 75) is the optimal balance for the vast majority of scenarios — 40-70% size reduction with virtually no visible quality loss, suitable for web images, emails, and social media posts. Extreme compression (quality 20) is suitable for avatars, thumbnails, and other size-critical scenarios. Light compression (quality 90) is suitable for product photos and photography requiring highest quality retention, only removing metadata and optimizing encoding.

**Format selection recommendations:** If the target platform supports it, prioritize converting images to WEBP or AVIF formats — these modern formats are 25-50% smaller than JPG at equivalent quality, and support transparent backgrounds and animation. This tool also provides image format conversion functionality.

This tool supports **11 mainstream image formats** (JPG/JPEG/PNG/WEBP/GIF/AVIF/BMP/ICO/HEIC/JXL/TIFF), including HEIC photos taken by Apple iPhones and next-generation AVIF format. Maximum single file size is 20MB, with batch compression displaying compression results for each image in real-time. Images are uploaded to servers for processing and **automatically deleted after 2 hours** to protect user privacy.

Use Cases

  • Web optimization: compress images to reduce page size, improve loading speed and SEO rankings (Core Web Vitals)
  • Email attachments: compress large images to fit within email attachment limits (typically 10-25MB)
  • Form uploads: compress images before submitting to applications, exam registrations, and resume systems with size limits
  • Social media posting: compress images for WhatsApp, Instagram, Twitter/X, Facebook and other platforms with size restrictions
  • E-commerce operations: batch compress product photos to improve store page loading speed
  • Format compatibility: compress and convert HEIC (Apple) format photos to universal JPG/WEBP

How to Use

  1. Click the upload area or drag and drop image files onto the page; batch adding supported (max 20MB per file)
  2. Select compression level: Recommended, Extreme, or Light compression
  3. Wait for compression to complete, view before/after size and compression ratio for each image
  4. Download compressed images individually or as a ZIP package; switch levels and re-compress if not satisfied

Features

  • Full coverage of 11 formats: supports JPG/JPEG/PNG/WEBP/GIF/AVIF/BMP/ICO/HEIC/JXL/TIFF, including Apple HEIC and next-gen AVIF
  • Three compression levels: Extreme (quality=20), Recommended (quality=75), Light (quality=90) to meet different needs
  • Batch compression support: add multiple images at once for queued processing, each showing before/after size and compression ratio independently
  • Real-time compression ratio display: shows file size change and compression percentage for each image; negative values indicate already optimized, no need to re-compress
  • ZIP package download: multiple compressed images can be downloaded together as a single ZIP file for convenience
  • Task history: automatically records recent compression jobs for easy re-download
  • Privacy protection: files uploaded to server for processing, automatically deleted after 2 hours, no other usage

FAQ

Will image compression make my photos blurry?

It depends on the compression level. Recommended compression (quality 75) shows virtually no visible quality difference for everyday web images, email attachments, and social media scenarios, while typically reducing file size by 40-70%. Use Light compression (quality 90) if you need to preserve maximum quality.

What image formats are supported?

Supports 11 mainstream formats: JPG/JPEG, PNG, WEBP, GIF, AVIF, BMP, ICO, HEIC, JXL, TIFF. This includes Apple iPhone HEIC format and next-generation AVIF format. Maximum single file size is 20MB.

Can I batch compress multiple images at once?

Yes, you can add multiple images for batch queued compression. Each image is processed independently with its compression ratio displayed. Ideal for batch processing e-commerce product photos, blog images, and social media assets. After processing you can download individually or as a ZIP package.

Are uploaded images secure? Will they be stored?

Images are uploaded via encrypted connection to compression servers for processing. After compression is complete, files are automatically deleted after 2 hours and will not be permanently stored or used for other purposes. Please download promptly after processing completes.

Which format gives the best compression: JPG, PNG, or WEBP?

If output format is optional, WEBP and AVIF offer the highest compression efficiency — 25-35% smaller than JPG at equivalent quality. If you must keep the original format, Recommended mode works best for JPG, leveraging human eye's higher sensitivity to brightness than chrominance for optimization.

Why did the file size increase after compression?

In rare cases, re-compressing an already highly compressed image may result in slightly larger file size. If the original is already a low-quality JPG (quality < 50), we recommend using Light compression mode. The tool displays compression ratio for each image; negative values indicate size increase, in which case you can choose to download the original.

Will image resolution change after compression?

No. Compression only changes the image data size (quality parameter) and does not alter pixel dimensions (width and height). If you need to reduce image dimensions simultaneously, please use the image resize tool.

Image Resizer

Glossary

Lossy Compression
A compression method that significantly reduces file size by discarding some data (primarily high-frequency chrominance information insensitive to the human eye). JPG, WEBP (default), and AVIF are lossy compression formats. High compression ratio but loses some quality; lower quality parameters result in more noticeable loss.
Lossless Compression
Reduces file size solely by optimizing data encoding without losing any pixel data. PNG, GIF, and WEBP (lossless mode) are lossless compression formats. Lower compression ratio but can perfectly reconstruct the original image, suitable for scenarios requiring pixel-perfect accuracy.
Quality Parameter
The core parameter in lossy compression, typically ranging from 0-100. Higher values mean better quality but larger file size. 75 is the optimal balance for most scenarios (recommended by Google PageSpeed), 20 for extreme compression, 90+ for high quality.
WEBP
An image format introduced by Google in 2010, supporting both lossy and lossless compression, transparency, and animation. 25-35% smaller than JPG and 26% smaller than PNG at equivalent quality, the recommended format for modern web use.Wikipedia - WebP
AVIF
A next-generation image format based on AV1 video encoding (released in 2019), offering approximately 20% better compression efficiency than WEBP, supporting HDR, wide color gamut, transparency, and animation. Natively supported in Chrome 85+ and Firefox 93+.Wikipedia - AVIF
HEIC/HEIF
High Efficiency Image File Format, the default photo storage format for Apple iPhones iOS 11+, with better compression ratios than JPG. However, compatibility is limited on Windows and some Android devices, often requiring conversion to JPG for use.
Core Web Vitals
Core web user experience metrics proposed by Google, where LCP (Largest Contentful Paint) is directly affected by image loading speed. Compressing and optimizing images is one of the most effective ways to improve LCP scores.
LCP (Largest Contentful Paint)
Measures the time when the main content of the page finishes loading. Google recommends LCP under 2.5 seconds. Compressing above-the-fold large images and using modern formats (WEBP/AVIF) are key to optimizing LCP.
Metadata
Additional information in image files beyond pixel data, such as EXIF (camera model, GPS location, timestamp), ICC Profile (color profile), etc. Removing metadata can reduce file size by several KB to tens of KB while also protecting shooting location privacy.
DPI/PPI
Dots/Pixels Per Inch, a unit of print resolution, which has no practical meaning for screen display. Screen display only cares about pixel dimensions (width × height); compression does not change DPI settings or pixel dimensions.

Three compression levels comparison

Compression levelQuality parameterTypical compression ratioImage qualitySuitable scenarios
Extreme compression2070-90%Lower, visible compression artifacts may appearAvatars, thumbnails, size-critical scenarios
Recommended compression7540-70%High, virtually indistinguishable to the naked eyeWeb images, email attachments, social media posts (recommended)
Light compression9010-30%Very high, completely visually losslessProduct photos, photography requiring highest quality retention

Common image format use cases comparison

FormatCompression typeBest use caseTransparencyAnimation
JPG/JPEGLossyPhotographs, realistic images❌❌
PNGLosslessIcons, screenshots, text images, transparency needed✅❌
WEBPLossy/LosslessWeb images (25-35% smaller than JPG/PNG)✅✅
AVIFLossy/LosslessNext-gen format (even smaller than WEBP)✅✅
GIFLossless (256 colors)Simple animations✅ (1-bit)✅
HEIC/HEIFLossyApple device photos✅❌

Authoritative References