Image Compressor

Why image size matters

Images are usually the heaviest part of a web page, an email or a document. A single photo straight from a phone can be 3 to 8 MB, while the same picture shown on a web page at 800 pixels wide needs perhaps 100 to 200 KB. Oversized images slow pages down, use visitors' mobile data, fill storage, and can push an email over its attachment limit. For websites, image weight is one of the biggest influences on loading speed and on Core Web Vitals scores.

Compression reduces the file size without changing what the picture looks like on a normal screen. Done well, you cannot tell the difference; done badly, you see blocky patches and blurry edges. The trick is choosing the right format, the right dimensions and the right quality.

How this compressor works

You can drop up to 30 images at once in JPG, PNG, WebP, GIF, BMP or AVIF format. Each one is redrawn in your browser and saved again as WebP or JPG at the quality you choose, with an optional limit on the longest side from 4K down to 800 pixels. For every image you see the exact size before and after, and you can download files one by one or all together as a ZIP.

Photos taken sideways on a phone come out the right way up, because the tool applies the orientation stored in the picture before it re-encodes it. Nothing is uploaded; the compression happens on your device, so private photos and client work stay private.

Choosing quality and dimensions

Two settings control almost all of the saving, and dimensions usually matter more than quality.

• Dimensions first. A 4,000 by 3,000 pixel photo has 12 million pixels. Shrinking it to 1,600 by 1,200 removes about 84 percent of the pixels before quality is even touched. Choose the longest side according to where the picture will be shown: 1,200 to 1,600 pixels covers most web pages and blog posts.
• Then quality. For JPG and WebP, 75 to 85 percent is the sweet spot. Below about 60 percent, blocking and blur become visible on photographs; above 90 percent, the file grows quickly for very little visible gain.
• Compare before you keep. Open a compressed image at full size and look at edges, faces and text. If it looks the same as the original at normal viewing size, you have found the right setting.

JPG, PNG or WebP?

JPG is the safe choice for photographs and works everywhere. PNG is lossless and keeps sharp edges and transparency, which suits screenshots, logos and diagrams, but photographs saved as PNG can be many times larger than the same picture as JPG. WebP handles both photographs and graphics and is typically 25 to 35 percent smaller than JPG at similar visual quality, and every current browser supports it.

If you are preparing images for a website, WebP is normally the best output. If the file is going to someone who may open it in older software, or you are uploading to a service that asks for JPG, choose JPG. For a deeper comparison of formats, read JPG vs PNG vs WebP, and for the website use case, how to compress images for a faster website.

Workflows that save the most

Start with the largest dimension you need, not the largest you have. Resize with the Image Resizer or crop away unneeded areas with the Image Cropper first, then compress. If your photos come from an iPhone in HEIC format, convert them with HEIC to JPG. If you are building a PDF from pictures, compress the images before using JPG to PDF, which keeps the finished document small.

Keep your originals. Compression is lossy, so store the full-quality file somewhere safe and use the compressed copy for sharing. Compressing an already compressed image again reduces quality further, so always start from the original.

Privacy and limits

Your images never leave your browser. There are no accounts and no server copies, which is why the tool works up to 30 files at once, using your own device memory. Very large images can be slow on older phones; if the page becomes unresponsive, process fewer files or reduce the maximum size. Animated GIFs are turned into a single still image, so keep the original if you need the animation.