Phone cameras produce files far larger than any screen needs. Upload a JPG, PNG or WebP above and it comes back smaller — for a faster website, an email that actually sends, or a document that is not fifty megabytes of photographs.
Below: the resize step most people skip that saves more than compression itself, why PNG and JPG shrink for completely different reasons, and the one thing you cannot undo.
This is the single biggest saving available, and almost nobody does it in the right order.
A modern phone photo is around 4000 pixels wide. A full-screen image on a laptop needs about 1920. A blog post image is usually displayed at 800. So a photograph uploaded straight from a camera is carrying four or five times more pixels than will ever be seen — and the file size grows with the square of the dimensions.
Halving the width and height quarters the pixel count. Before any compression is applied. Nothing else you can do to an image comes close to that saving.
Resize the image first, then compress what remains. The combination is far more effective than compression alone.
They use fundamentally different methods, which is why the same compression setting behaves so differently depending on the file.
JPEG is lossy. It permanently discards detail, choosing detail the eye is least likely to notice in continuous, gradual tones. That works beautifully on photographs and badly on text and sharp edges, where it produces faint halos. Compression here means discarding more, so there is a genuine quality trade being made.
PNG is lossless. Every pixel is reproduced exactly, so compressing a PNG means finding a more efficient way to describe the same image — simplifying the colour palette, stripping metadata, choosing better encoding. Savings are real but more modest, and nothing is thrown away.
The practical rule: photographs belong in JPG, where compression is dramatic and the loss invisible. Screenshots, diagrams, charts, logos and anything with text belong in PNG, where the edges stay crisp. Converting a screenshot to JPG to save space is a false economy — the text goes fuzzy and you cannot get it back.
Lossy compression is one-directional. Detail removed from a JPEG is gone, and no amount of decompressing, enlarging or converting to PNG will bring it back.
Two consequences worth taking seriously.
Keep your originals. Compress a copy and archive the full-size version, particularly for photographs you might later want to print or crop into. A compressed image cropped in half has half the detail it needed.
Do not compress repeatedly. Each round of JPEG compression discards a little more, and the damage accumulates — visible as blocky patches and colour banding in smooth areas like skies. An image that has been saved, emailed, downloaded, edited and re-saved several times has been through this cycle without anyone intending it. Always start from the original rather than a copy that has already been round the loop.
Images are typically the largest thing a web page downloads, so they dominate how fast it feels.
Google measures loading performance as part of how it assesses pages, and the metric that matters most — how long the largest visible element takes to appear — is usually a photograph. A homepage carrying six uncompressed phone photos is asking visitors on a mobile connection to download twenty-five megabytes before the page settles.
Two habits that help more than any plugin. Resize before uploading rather than letting the browser scale a huge image down — the full file still downloads either way. And convert photographs to WebP where you can, which typically reaches a similar quality at a noticeably smaller size than JPEG, and is supported by every current browser.
Camera images carry EXIF metadata alongside the picture — the make and model of the device, the exact date and time, camera settings, and often GPS coordinates recording precisely where the photo was taken.
For a holiday snapshot that is harmless. For a photo of something at your home, a workplace, or anywhere you would rather not publish the location of, it is a real disclosure that travels invisibly with the file. Many social platforms strip it on upload; plenty of forums, messaging apps and websites do not.
Compression tools often remove metadata as part of reducing file size, which is a useful side effect. If location privacy matters for a particular image, check the result rather than assume — on Windows, right-click the file, choose Properties, then Details.
Resize Image comes first for the biggest saving, HEIC to JPG converts iPhone photos to a usable format, JPG to PDF bundles photos into one document, and Compress PPTX shrinks a deck full of images. Browse all image tools.