Shrink your photos and screenshots to a fraction of their size while keeping them sharp. Learn which formats to use, how much compression is safe, and how to do it free in your browser.
By Ernzi Tools team · November 6, 2026
Large image files slow down websites, fill up inboxes, and eat mobile data. A single photo from a modern phone can be 5 MB or more — far bigger than it needs to be for a web page or a chat message. Image compression solves this by removing data your eyes barely notice. Done well, a compressed image looks identical to the original at a tenth of the size.
There are two kinds of compression. Lossless compression reorganizes the file without throwing any visual information away. It is safe for logos, icons, and screenshots, but it typically only shrinks a file by 10–30%. Lossy compression discards some fine detail — subtle color variations and high-frequency texture — and can shrink a photo by 70–90%. For photographs, lossy compression at a sensible quality level is almost always the right choice, because the discarded detail is invisible at normal viewing sizes.
The answer depends on the image. For photos you plan to show on a website, a JPEG quality setting of 75–85 is a good starting point: file sizes drop dramatically while the image still looks crisp. Below 60, you will start to see blocky artifacts around edges and in smooth areas such as skies. For PNG screenshots with text, prefer lossless or mild lossy compression, because text edges show artifacts first. A useful rule is to compare the result side by side with the original at 100% zoom before you publish it.
Sometimes the biggest win is switching formats. A PNG screenshot saved as a high-quality JPEG can drop from 2 MB to 200 KB. Modern WebP files are typically 25–35% smaller than equivalent JPEGs at the same visual quality, and they work in all current browsers. If your audience uses recent browsers, converting to WebP is often the single most effective optimization you can make.
Do not compress the same file twice — each lossy pass throws away more detail, and quality degrades fast. Always keep your original file and compress a copy. Do not upscale a small image and then compress it; you cannot add detail that was never there. And remember that compression cannot fix a blurry or badly lit photo — it only makes files smaller, not pictures better.
If you have dozens of images — a product catalog, a photo gallery, a blog archive — compressing them one by one is tedious. Work in batches instead: process all images for one page or one product at a time, using the same quality setting throughout so the results look consistent. Save the compressed files with clear names, keep the originals in a separate folder, and spot-check a few results at full size before you publish. A consistent workflow turns an afternoon of tedious work into a quick routine you can repeat whenever new images arrive.
Not every image needs the same treatment. Use these starting points and adjust by eye:
AVIF is the newest image format in wide use, and it compresses even better than WebP — often 20–30% smaller at the same visual quality — while supporting transparency and HDR color. All current versions of Chrome, Firefox, Safari, and Edge can display it. The catch is compatibility: older devices, email clients, and some social platforms still do not accept AVIF uploads, and encoding an AVIF file is slower than encoding a JPEG or WebP. For images on your own website, AVIF is worth trying with a JPEG or WebP fallback. For files you send to other people, stick with JPEG or PNG until AVIF support is universal.
With the right settings, most photos can be reduced to under 300 KB with no visible difference. That means faster pages, cheaper storage, and happier visitors — all from a one-minute task.
All tools are free and run entirely in your browser — your files never leave your device.