Which format should I choose?

AVIF has the best compression (up to 50 % smaller than WebP), but is slower to encode and only supported in newer browsers (Chrome 85+, Firefox 93+, Safari 16.4+). WebP is the sweet spot, near-universally supported since 2020 and 25–35 % better compression than JPEG. JPEG is safest for maximum compatibility (email, old systems). PNG only for graphics with transparency where you need losslessness.

What’s the difference between lossy and lossless?

Lossy discards data that can’t be recovered, compresses aggressively at some visual degradation. JPEG, lossy WebP and lossy AVIF are examples. Lossless preserves every pixel exactly, larger files but perfect reconstruction. PNG and lossless WebP are examples. Don’t re-compress a JPEG many times; each round adds new artefacts (generation loss).

How does the quality setting affect the result?

Quality 100 = least compression (nearly lossless for JPEG). Quality 80–85 is the default in most libraries, nearly invisible quality loss. Below 60, artefacts (blocking, ringing near edges) become visible. Photos usually work at 70–80. Sharp graphics and text screenshots often need 90+. Experiment, the browser has lightweight encoders and you can compare directly.

Does the tool change the resolution?

No, dimensions stay the same. If you need to scale the image down (e.g. 4000×3000 → 1920×1440), that’s the single most effective form of compression. Combine downscaling with format change to WebP for best results on websites.

/bilde-komprimering

Image Converter & Compressor - PNG, JPG, WebP, SVG

Convert image formats (including SVG to PNG/JPEG), resize dimensions, and compress files locally.

Image Converter & Compressor

Convert, compress, and resize images and SVG files locally in your browser.

Drag & drop an image here, or click to select

PNG, JPG, WEBP, AVIF, GIF, BMP, SVG

Name
Dimensions
Original
Compressed
Saved

How it works

This tool compresses, resizes, and converts your images completely locally in your browser using HTML5 Canvas and the File API. Your graphics are never sent to any server, ensuring your personal and sensitive images remain private.

What does this tool do?

Format conversion: Convert between JPG, PNG, WebP, AVIF, and SVG. For example, rasterize SVG vectors to crisp PNGs, or convert heavy PNG files to compact WebP formats.
Compression: For JPEG and WebP, adjust the quality factor to drastically reduce file sizes with almost no visible quality degradation.
Scaling: Resize pixel images by defining maximum width/height constraints, or scale vector SVG files (1x, 2x, 4x, etc.) without losing detail.

About this tool

Image compression reduces file size by discarding visual information imperceptible to the human eye. Modern formats like WebP and AVIF produce 25–50 % smaller files than traditional JPEG at equivalent visual quality. This tool lets you convert and compress images directly in the browser, pick a format (JPEG/WebP/AVIF/PNG), adjust quality (0–100), and compare before/after side by side. Useful for faster websites, email and mobile apps. All compression happens locally via `<canvas>` and the browser’s built-in image encoders; no files are uploaded.

How to use it

Drag and drop the image, or click "Choose file". JPEG, PNG, WebP and AVIF are supported.
Pick output format: WebP (great balance of quality/size), AVIF (best compression), JPEG (best compatibility).
Adjust quality with the slider: 70–85 is the sweet spot for most images.
Compare file size before and after, plus visual difference.
Download the compressed image, the file never leaves your browser.

Examples

Photo for website

InputIMG_4823.jpg (3.2 MB, JPEG 100%)

Outputcompressed.webp (420 KB, WebP 80), 87% smaller

Typical phone photo with low extra compression. WebP 80 gives a big size cut without visible quality loss.

Screenshot

Inputscreen.png (2,1 MB, PNG)

Outputscreen.webp (150 KB, WebP 90), 93% smaller

PNG is lossless but huge for screenshots. Lossy WebP gives the same visual impression at < 10 % of the size.

Logo

Inputlogo.png (85 KB, PNG with transparency)

Outputlogo.webp (14 KB, WebP lossless), 84% smaller

For logos with transparency, use WebP in lossless mode, preserves alpha and sharp edges.

Common use cases

Optimising images for websites, better Lighthouse scores and LCP.
Cutting weight of email newsletters so they load faster.
Sending images over email when the attachment limit (25 MB Gmail) blocks you.
Compressing screenshots for documentation and bug reports.
Preparing images for App Store / Play Store where app size matters.
Reducing storage in personal photo archives.

Frequently asked questions

Which format should I choose?: AVIF has the best compression (up to 50 % smaller than WebP), but is slower to encode and only supported in newer browsers (Chrome 85+, Firefox 93+, Safari 16.4+). WebP is the sweet spot, near-universally supported since 2020 and 25–35 % better compression than JPEG. JPEG is safest for maximum compatibility (email, old systems). PNG only for graphics with transparency where you need losslessness.
What’s the difference between lossy and lossless?: Lossy discards data that can’t be recovered, compresses aggressively at some visual degradation. JPEG, lossy WebP and lossy AVIF are examples. Lossless preserves every pixel exactly, larger files but perfect reconstruction. PNG and lossless WebP are examples. Don’t re-compress a JPEG many times; each round adds new artefacts (generation loss).
How does the quality setting affect the result?: Quality 100 = least compression (nearly lossless for JPEG). Quality 80–85 is the default in most libraries, nearly invisible quality loss. Below 60, artefacts (blocking, ringing near edges) become visible. Photos usually work at 70–80. Sharp graphics and text screenshots often need 90+. Experiment, the browser has lightweight encoders and you can compare directly.
Does the tool change the resolution?: No, dimensions stay the same. If you need to scale the image down (e.g. 4000×3000 → 1920×1440), that’s the single most effective form of compression. Combine downscaling with format change to WebP for best results on websites.

Technical background

JPEG (ISO/IEC 10918-1) uses DCT (discrete cosine transform) on 8×8 blocks + quantisation + Huffman coding. WebP (2010, Google) uses VP8 video coding for lossy and VP8L for lossless, with better entropy coding. AVIF (2019) builds on AV1 video compression and uses more advanced prediction modes. The tool uses `HTMLCanvasElement.toBlob(callback, type, quality)`, standardised in HTML5. The browser handles encoding via native code (often SIMD-accelerated). For batch processing use `OffscreenCanvas` and Web Workers. Metadata (EXIF, color profile) is typically stripped by the canvas roundtrip, worth knowing for RAW/pro workflows.