Image Compressor

What this image compressor does

This free online image compressor lets you compress JPEG, PNG, and WebP files without leaving your browser. Paste in a single photo or a whole folder of images, drag the quality slider to your preferred balance of sharpness and file size, optionally enter a maximum pixel width to resize while compressing, and download each result with one click. The tool shows you the before and after file size for every image so you can see exactly how much you saved. Because it runs client-side, your files never travel to a server and the tool works at full speed even on a slow connection.

Why compressed images matter for websites and SEO

Images are typically the largest assets on any web page, often accounting for 60 to 80 percent of total page weight. When a visitor lands on a page full of uncompressed photos, the browser has to download megabytes of data before it can finish rendering, which pushes up load times. Google measures this with Core Web Vitals metrics, particularly Largest Contentful Paint, which tracks how long it takes the biggest visible element on the page to load. A slow LCP score hurts both user experience and search rankings. Compressing every image on a page to the smallest acceptable quality is one of the highest-return performance optimisations available because it directly reduces the bytes the browser must fetch.

The SEO benefit compounds over time. Faster pages earn lower bounce rates, more pages per session, and better conversion rates, all signals that search engines interpret positively. A well-compressed product image gallery or blog post with optimised photos will consistently outperform the same content served with raw, uncompressed files, everything else being equal. Using this image size reducer as part of your publishing workflow is one of the simplest ways to improve rankings without touching a line of code.

Lossy vs lossless compression: which should you use?

Lossy compression permanently discards image data that the human eye is unlikely to notice, achieving dramatic reductions in file size. JPEG has always been lossy, and WebP supports a lossy mode that is even more efficient. At quality settings of 75 to 85, most viewers cannot spot the difference between a compressed JPEG and the original, even displayed at full screen. Lossless compression, used in the PNG format, reorganises and encodes data more efficiently without removing any of it, so the decompressed image is a perfect reconstruction of the original. Lossless files are larger, but they preserve every pixel exactly.

For photographs and images with lots of gradients and fine detail, lossy JPEG or WebP compression gives far smaller files than lossless PNG, with only minimal visible quality loss at sensible quality settings. For screenshots, diagrams, logos, and images with flat colours and sharp edges, lossless PNG compression keeps those crisp boundaries without the blocky artefacts that lossy compression can introduce in high-contrast areas. As a rule of thumb: use lossy JPEG or WebP for photos, and PNG for graphics where text or sharp edges must remain pixel-perfect.

How the quality slider works

The quality slider controls how aggressively the compressor discards image data during encoding. A setting of 100 keeps almost all detail and produces a file that is close in size to the original. A setting of 50 discards more data, giving a noticeably smaller file that may show slight blurring or JPEG blocking artefacts in detailed areas. For most web images, a quality setting between 70 and 85 hits the sweet spot: the image looks sharp at normal viewing sizes but the file is 60 to 80 percent smaller than the original. The tool shows you the resulting file size at your chosen quality before you download, so you can adjust the slider and instantly see the trade-off without committing to a download.

When to resize vs compress an image

Resizing and compressing address different aspects of file size. Resizing reduces the pixel dimensions of the image, which shrinks the file because there is simply less data to store. If you have a 4000-pixel-wide photo from a DSLR and you only need it displayed at 800 pixels on a website, resizing to 800 pixels removes 80 percent of the pixels before compression even begins. Compression then operates on a much smaller canvas, giving an even smaller final file. For maximum size reduction, combine both: resize to the largest dimension at which the image will actually be displayed, then apply compression at a quality setting of 75 to 85.

If the image dimensions are already appropriate for the use case, compression alone is usually the right move. Resizing below the display size would only make the image blurry when the browser scales it back up. This tool supports both operations simultaneously: enter a max width and a quality level and both transformations are applied in a single pass.

JPEG vs PNG vs WebP: choosing the right format

JPEG is the most widely supported format and the default for photographs on the web. It uses lossy compression tuned for continuous-tone images, and even at moderate compression levels it keeps photos looking excellent. PNG uses lossless compression and supports full transparency, making it the right choice for logos, icons, UI screenshots, and anything where you need a pixel-perfect result. WebP is a newer format from Google that supports both lossy and lossless modes as well as transparency, and it consistently produces smaller files than either JPEG or PNG at the same visual quality. All modern browsers support WebP, so choosing it for web images is a straightforward win on file size.

How to compress an image to a target size like 100KB

Many platforms impose a maximum upload size. Passport photos, forum avatars, and government document uploads often require files under 100KB, 200KB, or 500KB. The fastest approach is to start at quality 80 and check the file size the tool reports. If the output is still above your target, reduce the quality slider by 5 to 10 points and recheck. If the image is still too large after lowering quality significantly, also enter a smaller maximum width to resize the pixel dimensions down. Switching from PNG to JPEG or WebP before compressing can also make a large difference for photographic content, because PNG lossless encoding is inherently less space-efficient than lossy JPEG or WebP for photos.

Why browser-based image compression keeps your photos private

Many online image tools route your files through a remote server for processing. Your image is uploaded, processed on a machine you do not control, stored temporarily (or sometimes permanently), and then sent back. With this tool, all processing happens inside your browser using the Canvas and File APIs that are built into every modern browser. Your photos never leave your device. This matters for personal photographs, confidential product shots, medical images, legal documents, and any picture you would not want sitting on a stranger's server. There are no retention policies to read, no GDPR forms to accept, and no risk of your images appearing in a company's training data.

Batch compress images to save time

Compressing images one at a time is fine for a single hero image, but it becomes tedious when you have a folder of 20, 50, or 200 product photos, event pictures, or blog post images to prepare. The batch compression feature lets you drop all of them onto the tool at once. The same quality and resize settings are applied to every file, and you can download each compressed image as it finishes. For regular publishing workflows such as an e-commerce site that adds new product images weekly, batch compression is the feature that saves the most time.

Shrink images for email attachments

Email remains one of the most common ways people share photos, and attachment size limits are a regular source of frustration. Most email providers cap attachments at 10 to 25 MB, and many corporate email servers are stricter. A few uncompressed DSLR or modern smartphone photos can easily exceed that limit. Compressing a batch of photos to JPEG quality 80 before attaching them typically reduces a 30 MB group to under 5 MB, well within any attachment limit, while the images still look excellent when the recipient opens them on screen or prints them at standard sizes.

Compress images on a phone to free up storage

Modern smartphones capture photos at resolutions between 12 and 50 megapixels, producing raw files of 5 to 50 MB each. A year of casual photography can fill 64 GB of storage before you know it. Compressing photos you want to keep but no longer need at full resolution frees up significant space. Because this image compressor works on mobile browsers, you can open it on your phone, select photos from your camera roll, compress them at quality 75 to 80, and save the smaller versions. You can then decide whether to delete the originals or keep them as a backup. The tool is particularly useful before a trip when you need to make room for new photos.