How to reduce an image's file size
Two settings do almost all the work. Here are the numbers to use for email, forms, listings and websites.
Why the photo is 5 MB
A modern phone photo is around 4000 by 3000 pixels, saved at a quality setting near the maximum. That is right for printing a poster and wasteful for everything else. A screen shows at most about 2000 pixels across; an email preview shows 600. The file is big because it stores far more than anyone will see.
Setting 1: dimensions
Halving the width and height quarters the file size before any compression. Limit the longest side to 2000 pixels for a website or a screen, 1600 for an attachment, 1200 for a listing photo or a form upload, 800 for an avatar. The resize page does this for a batch at once and keeps the proportions.
Setting 2: JPG quality
JPG quality runs from 1 to 100. Phones save at about 95. At 80 the file is roughly a third of the size and nobody can tell the difference at normal viewing size; at 70 it is a quarter and still fine for photos; below 60, gradients and skin start to show blocks. The compress page has a slider and shows the size before and after, so you can go as low as looks acceptable.
Setting 3: the format
Screenshots and graphics are usually PNG, which is lossless and often large. A screenshot of a web page converted to JPG at quality 85 is a fifth of the size and looks the same; the PNG to JPG page does that. WebP is smaller than both at the same quality and is accepted by every current browser, but not by every form or email client. The format guide has the details.
Targets that come up
These settings hit common limits with room to spare:
- Under 1 MB (most forms, job portals): longest side 1600, quality 80.
- Under 500 KB (marketplaces, forums): longest side 1200, quality 75.
- Under 200 KB (avatars, ID photos, some government forms): longest side 800, quality 70.
- Email with ten photos: longest side 1600, quality 75, then send the zip the tool offers.
Doing it without uploading
Resizing and re-encoding are things a browser does natively, so there is no reason to send the photo to a compression website first, wait for the upload, and be told the third file needs a subscription. Stayput's image compressor uses the browser's own encoder on your device, handles hundreds of files in one go, and shows the size of each result. Re-encoding drops the EXIF block, including the GPS location, which is usually what you want for anything going online.
Questions
Does reducing file size reduce quality?
Reducing dimensions discards pixels you would not have seen; lowering JPG quality discards fine detail. Both are invisible at sensible settings, and both are irreversible, so keep the original.
How do I make a photo smaller on my phone?
Open the compress page in the phone's browser, pick the photos, set the size, and save the results. It works on iPhone and Android without an app, and offline once loaded.
Why is my PNG so big?
PNG is lossless, so a photo saved as PNG is several times the size of the same photo as JPG. Convert photos to JPG; keep PNG for screenshots with text and for transparency.
Can I compress without changing the dimensions?
Yes. Choose "Keep size" in the resize options and only the quality slider applies.