Are my images uploaded to a server when I compress them?

No. Culacc's image compressor runs entirely in your browser using JavaScript. Your image files are never sent to any server — they never leave your device. This is called browser-based or client-side compression, and it means your photos and images remain 100% private.

How much can I reduce an image file size?

Results vary depending on the image and format. JPEG images typically compress by 30–60%. PNG files converted to WebP typically compress by 60–80%. At the default 82% quality setting, the visual difference is indistinguishable in most cases. You can reduce the quality slider further for even smaller files.

Why does PNG compress so much more than JPEG?

PNG files use lossless compression, which preserves every pixel perfectly but results in larger files. Our tool converts PNG to WebP, which is a modern format that achieves similar visual quality using advanced lossy and lossless compression techniques — resulting in files 60–80% smaller than the original PNG.

What image formats are supported?

We support JPEG (.jpg, .jpeg), PNG (.png), and WebP (.webp) formats. PNG files are automatically converted to WebP for maximum file size reduction. JPEG and WebP files are recompressed while keeping their original format.

Will compression make my images look worse?

At the default 82% quality setting, the visual difference is imperceptible for most images — especially photos. If you are compressing images for web use, social media, or email, this setting is ideal. For professional printing or archival purposes, we recommend 90–95% quality.

Is there a file size or number limit?

Since compression happens in your browser, there are effectively no server-side limits. Very large images (50+ MB) may take a few seconds to process depending on your device. You can compress as many images as you want — there are no daily limits.

Can I compress multiple images at once?

Yes. Select multiple files using the file picker or drag and drop multiple images at once. Each image is compressed individually and you can see the before/after size for each one. Click 'Download All' to save all compressed images in one batch.

What is lossless vs lossy image compression?

Lossless compression reduces file size without discarding any image data — every pixel is preserved exactly. Lossy compression achieves much greater size reduction by discarding imperceptible image data. Our tool uses lossy compression with a quality setting you control. At 80%+ quality, the difference is visually indistinguishable for most images.

Browser-Based · Nothing Uploaded

Free Online
Image Compressor

Reduce JPEG, PNG, and WebP file size by up to 90% without losing quality. Compression happens entirely in your browser — your images never leave your device.

Images never uploaded

No account needed

JPEG, PNG, WebP supported

Batch compression

🖼️ Image Compressor

JPEG · PNG → WebP · WebP · Processed locally in your browser

Quality 82%

Max resolution

Presets

Processed locally — never uploaded

🖼️

Drop your images here

JPEG, PNG, WebP — multiple files supported

or paste from clipboard — Ctrl+V

Compressing...

Results

🔒

100% Private — Your Images Never Leave Your Device

Culacc's image compressor uses browser-based compression — all processing happens locally using JavaScript in your browser. This means your photos, documents, and screenshots are never uploaded to any server, never stored, and never analyzed. This is fundamentally different from most online compressors that require a server upload. Your files stay on your device at all times.

How to Use

Compress images in 3 steps

No software to install. Works on any device — desktop, mobile, or tablet. Your images never leave your browser.

Upload your images

Drag and drop JPEG, PNG, or WebP images into the upload area, or click "Choose Images." You can also paste directly from your clipboard with Ctrl+V.

Set your quality

Choose a quality preset (Web, Email, High Quality) or fine-tune the quality slider. Optionally set a maximum resolution to also resize the image.

Download compressed images

See the exact before and after file sizes for each image. Click Download to save, or use Download All for batch saving.

Why Browser-Based Compression is Better

Most online image compressors work by uploading your file to a remote server, compressing it there, and sending it back. This means your images — which may contain sensitive personal photos, business documents, or private screenshots — pass through a third party's systems.

Culacc's image compressor uses client-side compression, meaning the entire compression process runs locally in your browser using JavaScript. Your files never leave your device. This makes it faster (no upload/download time for large files), more private, and works even with a slow internet connection.

This approach is particularly important for sensitive images: medical photos, personal identification documents, confidential business screenshots, or anything you would not want stored on a stranger's server.

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PNG to WebP Conversion — Up to 80% Smaller

PNG files use lossless compression and tend to be very large. Our tool automatically converts PNG images to WebP format, a modern image format developed by Google that achieves dramatically smaller file sizes with the same visual quality. A 2 MB PNG screenshot typically becomes 200–500 KB WebP — with no visible difference. WebP is supported by all modern browsers and is the recommended format for web use.

Supported Formats

Which image formats can I compress?

.jpg

JPEG

Best for photos and complex images. Compressed using lossy recompression at your chosen quality level.

30–60% reduction

.png

PNG → WebP

Converted to WebP for maximum compression. PNG's lossless format is much larger than necessary for most web uses.

60–80% reduction

.webp

WebP

Already an efficient format. Recompressed at your chosen quality level to squeeze out additional savings.

20–40% reduction

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4.9 out of 5 — rated by 1,247 users

FAQ

Frequently asked questions

Everything about compressing images online.

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Store your compressed images in the cloud

Culacc gives you 5 GB free cloud storage with built-in compression on every upload. Organize, share, and access your images from any device.

Create Free Account — 5 GB Storage

No credit card required · EU servers · GDPR compliant

Free OnlineImage Compressor