Image Trình nén

What is Image Trình nén?

An image compressor reduces an image's file size by re-encoding it at a lower quality or with a more efficient codec. Smaller images load faster, save bandwidth, and improve page performance scores. The tool supports lossy compression (JPEG, WebP) where quality is traded for size, and lossless PNG optimization. All processing happens in the browser via the Canvas API — the image is never uploaded.

How It Works

The input image is drawn onto an offscreen <canvas> at its natural dimensions. The canvas is then re-encoded via toBlob() with a target MIME type (image/jpeg or image/webp) and a quality parameter (0-1). For PNG, the canvas re-encode applies lossless filtering. The resulting Blob is compared to the original; the user sees both sizes and the percentage saved before downloading. EXIF metadata is typically stripped during re-encode.

Common Use Cases

• Optimizing web images — shrink hero photos and product images before uploading to a CMS
• Reducing email attachment size — compress photos to stay under attachment limits
• Preparing social-media images — meet platform size recommendations without losing visible quality
• Cutting storage costs — batch-compress user-uploaded images to save disk and bandwidth

Technical Details

Engine: Canvas API (toBlob/toDataURL). Supported inputs: JPEG, PNG, WebP (browser-dependent). Quality: 0-1 for lossy formats; PNG ignores the quality parameter. Re-encoding strips most EXIF metadata. Output size depends on image content — flat areas compress better than noisy ones. Browser canvas implementations vary; Safari and Chrome may produce slightly different outputs.