Photoshop export too large? Use this Mac tool instead

You exported a JPEG from Photoshop at quality 60 and it’s still 4 MB. You did “Save for Web (Legacy)” because the new Export As dialog produces files even bigger. Somehow the same image runs through a free Mac tool and comes out half the size with no visible difference. What’s going on?

Why this happens

Photoshop’s JPEG encoder is libjpeg from 1995 with some Adobe-specific tuning. It’s reliable but not aggressive. The MozJPEG encoder — developed at Mozilla a decade ago — uses smarter trellis quantization, optimised Huffman tables, and progressive scan optimization. Same JPEG format, dramatically smaller files at the same visual quality. Photoshop doesn’t ship MozJPEG.

Same story for PNG: Photoshop’s PNG encoder is decent but doesn’t quantize. Tools like pngquant route 24-bit truecolour PNGs through palette quantization and get 60-85% reductions Photoshop can’t touch.

The native way (after Photoshop)

Export from Photoshop at high quality, then re-encode through a smaller tool. From Terminal:

For JPEG (MozJPEG-grade):

brew install mozjpeg && cjpeg -quality 80 photoshop-export.jpg > smaller.jpg

Note that MozJPEG’s cjpeg reads PPM, so you may need to convert from JPEG first via ImageMagick:

magick photoshop-export.jpg ppm:- | cjpeg -quality 80 > smaller.jpg

For PNG:

brew install pngquant && pngquant —quality=70-90 —strip photoshop-export.png

This is the same pipeline that tools like ImageOptim and TinyPNG use under the hood.

The faster way

Download Melt and skip the Terminal pipeline. Drag the Photoshop export in, get a smaller file out.

1. Download Melt and open it.
2. Drag the Photoshop export in.
3. Pick the same format (JPEG or PNG) and a quality — 80 for JPEG, 80 for PNG quantization.
4. Click Compress.

It runs the equivalent of MozJPEG (for JPEG) or pngquant (for PNG) under the hood. The output is functionally identical to what you’d get by stringing the Terminal commands above.

How much smaller will it really get?

A typical Photoshop JPEG export at quality 80 through MozJPEG/Melt: 25-40% smaller. A Photoshop PNG export through pngquant/Melt: 60-85% smaller. The PNG savings are especially dramatic because Photoshop doesn’t do palette quantization by default — you have to pick “PNG-8” manually, and even then the result is often larger than pngquant’s output.

Honest take

Photoshop is a great tool. JPEG and PNG encoding aren’t the things it’s great at. If your workflow is “design in Photoshop, then ship,” running the final exports through a dedicated compressor is genuinely the right move. You’d be running them through TinyPNG anyway — might as well do it offline.