Does the image compressor upload my photos to a server?

No. All processing happens entirely inside your browser using the HTML5 Canvas API. Your images never leave your device, and no data is transmitted to any server. This makes the tool completely private and safe for sensitive or personal photos.

What image formats are supported for input and output?

You can upload any browser-supported image format including JPEG, PNG, WebP, GIF, BMP, and AVIF. For output you can choose JPEG, PNG, or WebP. Note that compressing to PNG is lossless, so file sizes may not decrease as dramatically as with JPEG or WebP.

What quality setting should I use for web images?

A quality of 75–85% is the sweet spot for most web images. It delivers a visually imperceptible difference from the original while reducing file size by 40–60%. For hero images or photography, 80% is recommended. For thumbnails or background images, 60–70% can work well.

How does the Max Width and Max Height constraint work?

If you enter a max width, the image is scaled proportionally so its width does not exceed that value. If you also enter a max height, both constraints are applied independently — whichever reduction is larger wins, preserving aspect ratio. Setting either field to 0 disables that constraint.

Why is my PNG file sometimes larger after compression?

PNG uses lossless compression, so the quality slider does not reduce its fidelity. If you convert a simple image to PNG, the browser's encoder may produce a larger file than the original JPEG due to the lossless nature. Switch the output format to JPEG or WebP for better size reduction.

Can I compress multiple images at once?

Yes. You can drag and drop multiple image files onto the upload area at once, or use the file picker to select multiple files. Each image is processed individually and appears with its own before/after stats and download button. Click 'Download All' to save every compressed image in one action.

Does resizing affect image quality?

Resizing uses the browser's built-in bilinear interpolation through the Canvas API, which produces smooth results. Downscaling an image (reducing dimensions) generally looks excellent. Upscaling (enlarging beyond original size) is not recommended as it will appear blurry — this tool intentionally prevents upscaling.

What is the difference between JPEG quality 80% and 90%?

At 80%, most photos show no visible degradation at normal viewing distances, and file sizes are roughly 40–50% smaller than the original. At 90%, quality is virtually identical to the original but files are only 20–30% smaller. For web use, 80% gives the best file-size-to-quality ratio.

Browser Image Compressor & Resizer

Compress and resize JPEG, PNG, or WebP images entirely inside your browser — no server uploads, no account required. Adjust quality, cap dimensions, and batch-process multiple files in seconds. Your photos stay private on your device throughout the entire process.

By Lisa Chen, Digital Media Specialist • Last Updated: September 20, 2026

Image Compressor & Resizer

🖼️

Drag & drop images here

or click to browse — supports JPEG, PNG, WebP, GIF, and more

Quality: 80%

Max Width (px, 0=none)

Max Height (px, 0=none)

Output Format

How to Use the Image Compressor

Upload images — drag and drop one or more image files onto the upload area, or click it to open the file browser. You can select multiple files at once for batch processing.
Set quality — adjust the quality slider from 10% (smallest file, most loss) to 100% (lossless). A value between 75% and 85% is ideal for most web use cases.
Set dimension limits — enter a Max Width and/or Max Height in pixels to scale images down. Leave both at 0 to skip resizing and only apply quality compression.
Choose output format — select JPEG for photos (smaller files), PNG for images needing transparency (lossless), or WebP for modern browsers (best compression ratio).
Compress — click "Compress Images". Each image is processed in your browser using the Canvas API. Results appear below with original vs. compressed stats.
Download — click the individual "Download" button for a single image, or click "Download All" to save every compressed image at once.

What Is an Image Compressor?

An image compressor reduces the file size of digital images by applying lossy or lossless encoding techniques. For JPEG and WebP formats, a quality parameter controls how aggressively redundant visual data is discarded — lower quality means smaller files but more visible artifacts. For PNG, compression is always lossless, meaning all visual data is preserved but the encoding is optimised for fewer bytes.

This browser-based tool uses the HTML5 Canvas API to perform all compression locally. When you upload a file, it is read with the FileReader API, drawn onto an off-screen canvas at the desired output dimensions, and then exported via canvas.toBlob() at your chosen format and quality. The resulting blob is made available as a download link — your original file is never transmitted anywhere.

Image optimisation is one of the highest-impact performance improvements you can make to a website. According to web performance research, images typically account for 50–70% of total page weight. Reducing image sizes by 40–60% directly translates to faster page loads, lower bandwidth consumption, and better Core Web Vitals scores — all of which positively influence both user experience and SEO rankings. This tool gives developers, designers, and content creators a fast, private, zero-dependency way to prepare images for the web.

Key Features

100% client-side processing — images are never uploaded to a server; all computation happens in the browser using the Canvas API, ensuring complete privacy.
Batch compression — drag and drop or select multiple image files simultaneously and compress them all in one click, with individual results for each file.
Adjustable quality slider (10–100%) — fine-tune the compression level to balance visual fidelity against file size, with the percentage displayed live.
Proportional resizing — specify max width and/or max height constraints; the tool scales images proportionally, always preserving the original aspect ratio.
Three output formats — choose JPEG for maximum compatibility, PNG for lossless transparency, or WebP for cutting-edge compression with modern browser support.
Before/after stats per image — see original vs. compressed dimensions, file sizes in KB, and the percentage of space saved (or any increase) for every image processed.

Common Use Cases

Website optimisation: Reduce hero images, product photos, and blog thumbnails before uploading to a CMS. Smaller images load faster, improving Core Web Vitals metrics like Largest Contentful Paint (LCP).
Email marketing: Email clients often block or delay large images. Compressing banners and promotional graphics to under 100 KB ensures reliable rendering and faster inbox load times for recipients.
Social media uploads: Platforms like Instagram and LinkedIn re-compress images server-side, often introducing artifacts. Pre-compressing at a controlled quality level helps maintain visual quality after the platform's own processing.
Mobile app assets: App icons, splash screens, and in-app images must meet tight size budgets. Use the resizer to scale images to exact dimensions and the compressor to hit binary size targets.

Best Practices vs. Common Mistakes

✅ Best Practice	❌ Common Mistake
Use 75–85% quality for photographic JPEG images destined for the web	Using 100% quality for web images, bloating file sizes without visible benefit
Choose WebP for modern web projects to get ~30% smaller files than JPEG	Always outputting PNG, resulting in unnecessarily large files for photographs
Set a Max Width matching your layout's maximum display width (e.g. 1200px)	Uploading 4000px originals that are only displayed at 800px, wasting bandwidth
Compress images before uploading to a CMS or S3 bucket	Relying solely on server-side compression, which is often inconsistent or absent
Use PNG only when you need true transparency (alpha channel)	Using PNG for photos with no transparency, increasing file size 3–5× vs. JPEG

Format Comparison Cheat Sheet

Format	Compression	Transparency	Best For	Browser Support
JPEG	Lossy	No	Photographs, complex images	Universal
PNG	Lossless	Yes (alpha)	Logos, UI elements, screenshots	Universal
WebP	Lossy + Lossless	Yes	All web images	95%+ (all modern)
GIF	Lossless (8-bit)	1-bit	Simple animations	Universal
AVIF	Lossy + Lossless	Yes	Next-gen images	85%+ (modern)
SVG	Vector (XML)	Yes	Icons, logos, illustrations	Universal

Your Privacy Is Guaranteed

This tool is entirely client-side. When you drag an image into the upload area, it is read directly from your local disk into browser memory using the FileReader and URL.createObjectURL APIs. The compression canvas computation takes place entirely in your browser's JavaScript engine. No image data, metadata, EXIF information, or filenames are ever transmitted to any server. You can use this tool offline once the page has loaded. There are no analytics trackers on image content, no server logs of your files, and no account required.

Frequently Asked Questions

Does the image compressor upload my photos to a server?: No. All processing happens entirely inside your browser using the HTML5 Canvas API. Your images never leave your device, and no data is transmitted to any server. This makes the tool completely private and safe for sensitive or personal photos.
What image formats are supported for input and output?: You can upload any browser-supported image format including JPEG, PNG, WebP, GIF, BMP, and AVIF. For output you can choose JPEG, PNG, or WebP. Note that compressing to PNG is lossless, so file sizes may not decrease as dramatically as with JPEG or WebP.
What quality setting should I use for web images?: A quality of 75–85% is the sweet spot for most web images. It delivers a visually imperceptible difference from the original while reducing file size by 40–60%. For hero images or photography, 80% is recommended. For thumbnails or background images, 60–70% can work well.
How does the Max Width and Max Height constraint work?: If you enter a max width, the image is scaled proportionally so its width does not exceed that value. If you also enter a max height, both constraints are applied — whichever reduction is larger wins, preserving aspect ratio. Setting either field to 0 disables that constraint.
Why is my PNG file sometimes larger after compression?: PNG uses lossless compression, so the quality slider does not reduce its fidelity. If you convert a complex photograph to PNG, the browser's encoder may produce a larger file than the original JPEG. Switch to JPEG or WebP output for better size reduction with photographic content.
Can I compress multiple images at once?: Yes. You can drag and drop multiple image files onto the upload area at once, or use the file picker to select multiple files. Each image is processed individually and appears with its own before/after stats and download button. Click "Download All" to save every compressed image in one action.
Does resizing affect image quality?: Resizing uses the browser's built-in bilinear interpolation through the Canvas API, which produces smooth results. Downscaling an image (reducing dimensions) generally looks excellent. Upscaling (enlarging beyond original size) is not recommended as it will appear blurry — this tool intentionally prevents upscaling.
What is the difference between JPEG quality 80% and 90%?: At 80%, most photos show no visible degradation at normal viewing distances, and file sizes are roughly 40–50% smaller than the original. At 90%, quality is virtually identical to the original but files are only 20–30% smaller. For web use, 80% gives the best file-size-to-quality ratio.