How PhotoShrinker works
Most online compressors upload your photos to a server, process them there, then send them back. PhotoShrinker does the opposite: the entire pipeline runs inside your browser tab, on your own device. Here is what actually happens between the moment you drop a file and the moment your ZIP finishes downloading.
The four-stage pipeline
1. Decode
When you drop a file, your browser — not a server — reads it into memory and decodes the pixels onto a canvas. iPhone HEIC/HEIF photos are transcoded first, right on your device, so they can be processed like any other image.
2. Resize (optional)
If you pick 1920px or 1200px in the Resize control, the image is downscaled before encoding. Shrinking a 6000px camera photo to web dimensions often saves more space than compression alone.
3. Re-encode
The pixels are re-encoded as JPEG or WEBP at your chosen quality level. Compression removes the information the human eye notices least — you keep the look and drop the bytes.
4. Package
Finished images are bundled into a single ZIP archive, built entirely in your browser, and handed to you as a normal download. Nothing was ever transmitted anywhere.
Why running locally matters
Privacy by architecture, not by promise. Because there is no upload step, there is nothing to store, lose or leak. Family photos, client work and confidential graphics stay on your machine the whole time.
Speed without waiting rooms. Server-based tools spend time uploading your files, queuing them, and downloading the results. Local processing skips all of that — compression starts instantly, and heavy work runs in Web Workers so the page never freezes.
It works offline. Once the page has loaded, you can disconnect entirely and keep compressing. That is the simplest proof that your images never travel anywhere.
Quality presets explained
JPEG and WEBP are lossy formats: encoding discards information, and the quality setting decides how much. PhotoShrinker exposes that decision as four clear presets:
High Quality
Near-lossless output for photos you may print or edit further. Keeps maximum detail and sharpness.
Balanced (recommended)
The sweet spot for web, email and social media — big size savings with differences invisible at normal viewing distance.
Smallest Size
Maximum reduction for thumbnails, chat attachments and freeing up storage space.
Custom
A quality slider from 10% to 100% for full control over the size/quality trade-off, image by image.
What happens to your files
Your images live in your browser's memory while you work with them. That is what lets you re-download the ZIP or compare results without recompressing. When you remove a file, clear the batch or reload the page, PhotoShrinker revokes the temporary preview references and releases the binary data — no trace is left behind, and no copy ever existed outside your device.
In short: decode → (optional) resize → re-encode → ZIP. Four stages, zero uploads, and a batch of optimized images in one download.
Try it yourself
Free, private, no watermark — compress your first image in seconds.