ImageAlchemyCompression Studio

Reduce JPEG file size — free, private, in your browser

Shrink JPEG and JPG files without installing software. Batch compress with MozJPEG-grade encoding, preview before and after, and download individually or as a ZIP.

When to use JPEG

JPEG is the most compatible image format on earth — every browser, email client and device reads it. Use it when you need maximum compatibility or your platform doesn't support AVIF/WebP. For modern websites, those formats are better choices.

How much you can save

A JPEG exported at quality 100 from a camera or editor is typically 40–60% larger than it needs to be. Re-compressing at quality 80 with MozJPEG's progressive + trellis settings recovers most of that with no visible difference.

Why the encoder matters

Not all JPEGs are equal. MozJPEG is Mozilla's improved JPEG encoder that produces files roughly 10–15% smaller at the same visual quality, using trellis quantization and progressive encoding. ImageAlchemy uses it — most online compressors don't.

Quality recommendations

80 for photographs shown at full width. 70–75 for content images and thumbnails. 90+ only for portfolio images where you want to preserve fine texture. Never use quality 100 — it bloats files for invisible gains.

Progressive JPEG

Progressive JPEGs load in passes, showing a low-quality version quickly before refining. They're typically smaller than baseline JPEGs and perceived as faster. ImageAlchemy outputs progressive JPEG by default.

How to compress a JPEG with ImageAlchemy

1. Drop your JPEG files. 2. Keep JPEG as the output format. 3. Set quality (80 default) and max dimension. 4. Compress and download. Up to 200 images per batch, entirely on-device.

Related guides

WebP compressorAVIF compressor9 ways to reduce image file sizeWhat is MozJPEG?

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Frequently asked questions

Re-compress it at quality 80 with a modern encoder (MozJPEG with progressive and trellis settings) and resize to the dimensions it's actually displayed at. That typically cuts a quality-100 JPEG by 40–60% with no visible difference. ImageAlchemy does all of this in the browser.

80 for most photographs. Below 70 you start to see blocking artifacts; above 90 you pay a large file-size penalty for gains no one can see. Quality 100 is almost never correct for web use.

MozJPEG is Mozilla's improved JPEG encoder. Using trellis quantization and progressive encoding, it produces JPEG files roughly 10–15% smaller than standard encoders at the same visual quality. Most online JPEG compressors don't use it.

A progressive JPEG encodes the image in passes from coarse to fine, so a blurry version appears immediately and refines as it downloads. Progressive JPEGs are usually smaller than baseline ones and are perceived as faster by users.

Yes. ImageAlchemy runs MozJPEG-grade encoding locally in your browser via WebAssembly. Files never leave your device, no account is needed, and up to 200 images can be processed per batch.