Large images are the single most common cause of slow web pages. A photo straight from a phone camera is routinely 4–8 MB; the same image, compressed properly, is often under 300 KB with no difference a visitor would notice. This compressor runs entirely in your browser — your images are never uploaded anywhere.
How to use the Image Compressor
- Drop your images onto the upload area, or click to browse (up to 20 at once)
- Adjust the quality slider — 80% is a good starting point
- Compare the before and after size shown on each image
- Download individually, or use Download All for the whole batch
How image compression actually works
JPEG and WebP use lossy compression: they discard detail the human eye is poor at noticing, particularly fine colour variation. The quality slider controls how aggressive that discarding is. At 80% quality most photographs are visually identical to the original at roughly a quarter of the file size, which is why 80% is the default here.
PNG is lossless — it never discards data, so it stays larger. If your PNG is a photograph rather than a logo or screenshot, converting it to JPEG or WebP will usually save far more than compressing it as PNG.
Choosing a quality setting
- 90–100% — near-lossless. Use for print, photography portfolios, or images that will be edited again.
- 75–85% — the sweet spot for web use. Large savings, no visible artefacts on most photos.
- 50–70% — noticeable softening on detailed images, but fine for thumbnails and background images.
- Below 50% — visible blocking and colour banding. Rarely worth it.
Images with sharp edges and flat colour — logos, screenshots, diagrams, text — show compression artefacts much earlier than photographs. Keep those above 85%, or use PNG.
Frequently asked questions
Are my images uploaded to a server?
No. Compression happens entirely in your browser using the Canvas API. Your images never leave your device, which is why this works offline and why there is no file size limit imposed by a server.
How much smaller will my image get?
It depends heavily on the source. Photos from a phone or DSLR typically drop 70–90% at 80% quality. Images that have already been compressed once will shrink far less, because the easily-discarded detail is already gone.
Does compressing twice make it smaller again?
Barely, and it degrades quality each time. Lossy compression is not reversible — each pass discards more real detail. Always compress from the original file rather than re-compressing an already-compressed image.
Which format should I use for the web?
WebP for almost everything — it is typically 25–35% smaller than JPEG at equivalent quality and is supported by every current browser. Keep JPEG as a fallback only if you need to support very old browsers.
Will compression remove my EXIF data?
Yes. Re-encoding through Canvas drops metadata including camera settings and GPS coordinates. That is usually desirable for images you are publishing. Use the Image Metadata Viewer first if you want to check what is in the original.