Reduce Image Size
The effective order: cut oversized dimensions first, then compress, in one local pass. Preset to a 1920-pixel longest side with quality 80, honest per-file results, batch ZIP. Nothing uploads.
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JPEG, PNG, WebP · verified by file signature · processed one by one within this device's memory budget · nothing is uploaded
Browser encoder; bytes vary slightly between browsers.
Lossless OxiPNG optimization: pixels stay identical, so there is no quality setting. Convert to JPEG or WebP for lossy savings.
Why dimensions come first
Compression works within the pixels it is given; resizing changes how many pixels there are. Squeezing a 12-megapixel photo to 200 KB forces visible artifacts, while the same photo at 1920 pixels reaches 200 KB looking clean. The web rarely needs more than 1920 pixels of width (2560 for full-bleed hero images on large screens), and this page applies that ceiling automatically while leaving smaller images untouched. Then quality does the rest, and the compare slider proves it per file.
Three ways to make an image smaller, and which to use
Image size means three different things: pixel dimensions, file size in bytes, and the size it is displayed at. Reducing the pixel dimensions is the most effective way to cut bytes, because bytes scale with the number of pixels: halving width and height removes three quarters of them. Re-encoding at a lower quality cuts bytes without touching dimensions, and converting to WebP or AVIF cuts bytes at the same quality by using a better codec.
A worked example: a 3,840 by 2,160 screenshot saved as PNG is often 3 to 5 MB. Resized to 1,920 wide it is about a quarter of that; converted to WebP lossless it drops again by 25 to 40 percent; if it is a photo rather than a screenshot, lossy WebP at quality 80 takes it to a few hundred KB. This page applies the steps in that order and shows what each one saved.
File size misleads when it is reduced below what the display needs. An image shown at 1,200 pixels wide on a retina screen is rendered from 2,400 pixels, so resizing it to 1,200 makes it soft on exactly the devices your visitors use most. Resize to about twice the displayed width for photos, keep screenshots at their native size or an exact 2x or 1x reduction, and let quality and format do the rest.
Reduce image size FAQ
What reduces image size the most?
Dimensions, by far. File size scales with pixel count: a 4000x3000 photo has 12 million pixels, and displayed in a 1200-pixel-wide article it carries about 10x more data than needed. Halving both dimensions quarters the pixels before any quality tradeoff. This page presets a 1920-pixel longest side, the practical ceiling for full-width web images, and then compresses on top of it.
Image dimensions versus file size: what is the difference?
Dimensions are pixels (4000x3000); file size is bytes (3.2 MB). They are related but not locked: the same dimensions can be 500 KB or 5 MB depending on format, content and quality. Upload forms usually limit bytes, layouts care about pixels. This tool shows both for every file, before and after, so you can see which lever did the work.
Will resizing blur my images?
Downscaling done properly loses detail you could not display anyway; it should not look blurry at the display size. The tool uses the browser’s high-quality scaling mode and never upscales: an image already smaller than the target keeps its dimensions, because inventing pixels only adds blur. Check the per-file compare if a particular image matters.
Can I reduce many images at once?
Up to 20 per batch through a memory-bounded queue, with per-file results, remove and retry, and one ZIP download including an optional manifest of every size change. Oversized files that would exceed the device memory budget are refused up front with the reason, instead of crashing the tab halfway through a batch.
More free tools: Image Compressor · Image Resizer · To 1 MB · To 100 KB