How the image compressor works
Last updated 10 November 2026
Phone photos are often several megabytes. For most uses a much smaller file looks just as good.
How it works
- Choose the images, a quality and a format.
- The picture is redrawn and saved at that quality. A longest-side limit shrinks the size too.
- The result shows the before and after sizes.
Why shrink a photo
A photo from a recent phone can be several megabytes. Email attachments, online application forms and websites often have size limits, and big files are slow on mobile data. Compressing the picture makes it smaller while keeping it good enough for its job.
The three controls
- Quality: lower quality gives a smaller file and more visible blur or blocks. For photos, a middle setting is usually a good start.
- Format: JPEG suits photos. WebP is often smaller still but not every site accepts it. PNG keeps sharp edges and transparency but is larger for photos.
- Longest side: limiting the width or height in pixels can shrink a file far more than quality alone, because there are fewer pixels to store.
Reading the result
For each picture the tool shows the size before and after, so you can see what you saved. If the new file is still too large for a form, lower the quality a little or reduce the longest side, then run it again from your original.
Keep your originals
Compression throws away detail that cannot be brought back. Always compress a copy, not the only version of a photo. Compressing an already compressed file again loses more quality each time, so start from the original whenever you can.
Private by design
The pictures are processed inside your browser using your own device. They are not uploaded to a server, and nothing is kept once you close the page.
A sensible order of steps
- Check the size you need with the image dimensions tool.
- Resize to the pixel size the site needs, if there is one.
- Compress with a middle quality and look at the result.
- Lower the quality a little at a time until the file is small enough, always starting again from the original.
Why the file size drops
Most of the space in a photo goes on fine detail that is hard to see. Compression stores that detail less carefully. A smaller picture in pixels also has less to store. Together they can shrink a photo to a fraction of its size with little visible change on a phone screen.
When not to compress
Skip compression for pictures you plan to print large or edit further. Also avoid it for scans of documents where small text must stay sharp. In those cases a modest resize is usually safer than a heavy drop in quality.
Things to watch
- Each save loses some quality. Keep your originals.
- PNG pictures with transparency become JPEG with a white background.
Like every tool on MoneyMzansi, this one runs entirely in your browser. There is no account, no upload and no sign-up. Your files are read and processed on your own device, and nothing is kept once you close the page.