About the Image Compressor
Most photos coming off a phone are two to six megabytes, and most of that weight is invisible on a screen. This compressor redraws each image at the quality you choose and, if you want, at a smaller maximum width — the two changes that account for almost all of the savings. You see the before and after size for every file before downloading anything.
Why image weight decides how fast your page feels
On a typical web page, images account for more transferred bytes than everything else combined — the HTML, the stylesheets and the scripts together are usually a fraction of a single uncompressed photograph. That makes image weight the first thing to fix when a site feels slow, and often the only thing that needs fixing.
It also shows up directly in the measurements Google uses. Largest Contentful Paint, the metric that records when the biggest visible element has finished loading, is an image on most pages. Cut the size of that image and the number moves immediately, in a way that reordering scripts or trimming CSS rarely matches.
What compression actually changes
JPG and WebP are lossy formats: they discard information the human eye is poor at noticing, mostly fine colour variation, while preserving brightness detail, which we are very sensitive to. The quality setting controls how aggressive that discarding is. At 90 the file keeps almost everything; at 70 it throws away a surprising amount and looks nearly identical; at 40 you start seeing blocky patches around edges and in flat areas like skies.
The relationship is not linear. Going from 100 to 80 often removes more than half the file size with no visible change at all. Going from 80 to 60 saves much less and costs much more. That is why 70 to 80 is the range almost every guide lands on, and why this tool opens there.
Resizing usually saves more than the quality slider
A phone photograph is commonly 4000 pixels wide. A blog post displays it at perhaps 800 pixels, or 1600 on a high-density screen. The other 2400 pixels of width are downloaded, decoded and then thrown away by the browser. Since file size scales with the number of pixels, halving the width cuts the data to roughly a quarter before any quality change at all.
That is what the maximum width setting is for. Decide the widest the image will ever be displayed, double it for retina screens, and cap it there. For most content images that means 1600 pixels; for thumbnails and avatars, far less. Combine that with 75% quality and a five megabyte photo routinely comes out under 150 KB.
Choosing between JPG and WebP
WebP was designed to replace both JPG and PNG, and at equivalent visual quality it is typically 25 to 35% smaller than JPG. Every current browser supports it, including Safari since 2020, so compatibility is no longer a serious objection for web use.
JPG still wins in two situations: when the file has to be opened by older software, printers or corporate systems, and when you are sending it to someone whose tools you cannot predict. For anything that lives on a website you control, WebP is the better default.
Images this tool will not help much with
Screenshots, logos, line art and anything with flat colour and sharp text edges compress badly in JPG. The format smears the boundaries between colours, which is invisible in a photograph and painfully obvious around text. For those, keep PNG, or export WebP in a lossless mode from a dedicated editor.
Images with transparency are the other case. JPG cannot store an alpha channel at all, so this tool fills transparency with white when you choose JPG. If the transparency matters, convert to WebP or stay with PNG.
Compressing a batch properly
When you process a folder of photographs at once, use the same settings for all of them only if they are the same kind of image. A set of product photos on a white background tolerates far heavier compression than a set of detailed landscapes. If the results look uneven, split the batch and run the difficult images at a higher quality.
Always check the worst case rather than the average. Open the largest and the most detailed image from the batch at full size before you accept the settings. If those two look right, the rest will.
Why nothing is uploaded
Compression here uses the canvas engine built into your browser: the image is decoded, redrawn at the size you asked for, and re-encoded by the same code that saves images in any web application. No network request is involved at any point.
That matters more than it sounds. Client photographs, unreleased product shots, screenshots containing customer data and scans of documents are exactly the files people casually drop into online converters. Here they stay on your machine, and closing the tab is all the cleanup required.
How to use the Image Compressor
- Drop in one image or a whole batch of them.
- Move the quality slider — 70% is the usual sweet spot for photographs.
- Choose JPG for maximum compatibility or WebP for noticeably smaller files.
- Set a maximum width if the image is larger than it will ever be displayed, then download.
Why use this tool?
Batch compression
Load a folder of photos at once; each one is processed and listed with its own before and after size.
Resize while compressing
Capping width at 1600 or 1200 pixels often saves more than the quality slider does, because large photos carry detail no screen shows.
Completely private
Compression happens with the canvas engine inside your browser. No image is uploaded, so client photos and screenshots stay confidential.
Frequently asked questions
How small should a web image be?
Aim for under 200 KB for a typical content image and under 400 KB for a full-width hero. Anything above a megabyte will visibly slow a page on mobile data.
Will compression ruin the quality?
At 70 to 80% quality the difference is invisible at normal viewing size on photographs. Screenshots, flat illustrations and text-heavy images suffer more, so keep those above 85% or use PNG.
Should I use WebP or JPG?
WebP is typically 25 to 35% smaller at the same visual quality and is supported by every current browser. Use JPG when the file has to open in older software or be emailed to someone with unknown tools.