Compress images in your browser — no upload, no waiting
Photos straight off a phone or camera are often far bigger than they need to be for email, websites, or messaging apps. DocZap's Compress Image tool shrinks JPG, PNG, and WEBP files in batches, directly on your device, showing you exactly how much space each image saved before you download the result.
How DocZap shrinks your images
DocZap uses the open-source browser-image-compression library, which runs entirely inside a background Web Worker in your browser. It intelligently reduces file size by adjusting compression quality and, if needed, scaling down extremely large images while preserving their aspect ratio — all without a visible drop in quality for typical photos. Choose between three presets: High quality for images you plan to print, Recommended for everyday sharing, or Smallest size when minimizing file size matters most.
Why local compression keeps your photos private
Many free image compressors upload your photos to a server, compress them there, and send back the result — meaning your images, which might include personal photos, screenshots of private conversations, or business documents, briefly exist on infrastructure you don't control. DocZap avoids this entirely: compression runs inside your own browser's Web Worker, so your images are never transmitted over the network at any point in the process.
Common reasons to compress images
Compression comes up constantly: shrinking photos before uploading them to a website with strict size limits, reducing attachment sizes before emailing a batch of images, preparing product photos for a faster-loading online store, or saving storage space when archiving a large photo library. Because DocZap processes images in a batch and runs entirely client-side, you can compress dozens of photos at once without hitting an upload limit or waiting in a processing queue.
Getting the best results from batch compression
When compressing a batch of mixed photos, keep in mind that the same preset is applied to every image in the group, so results will vary depending on each photo's original size and content. A folder of already-small screenshots may barely shrink further at any setting, while large, high-resolution camera photos will usually see the biggest gains. If you're preparing images for a specific platform with a known size limit, Smallest size is the safest choice to guarantee every file clears that bar; if quality matters more and you just want to trim excess file weight, Recommended is a safer middle ground that rarely introduces visible artifacts.
DocZap's compressor works the same way on a laptop, a phone, or a tablet, since the Web Worker doing the actual compression is just as available on mobile browsers as on desktop ones. That makes it convenient to shrink a batch of photos straight from your phone's camera roll before sending them over a slow connection, without needing to plug into a computer first.
Need to turn your compressed images into a single document? Check out DocZap's JPG to PDF tool below, along with other tools to merge and organize your files.