How to compress photos on iPhone
Updated
The quickest way: open compresso.space in Safari, pick photos from your library and download the compressed copies. No app, no account, and iPhone HEIC photos come back as JPEG files that open everywhere.
Why iPhone photos are large, and why HEIC causes trouble
A modern iPhone shoots photos with 12 to 48 megapixels, so a single picture often weighs 2 to 6 MB. To save space, the camera stores photos in HEIC format by default. HEIC files can be up to about half the size of an equivalent JPEG, which is great on the phone itself.
The trouble starts when you share them. Many websites, application forms, older Windows computers and online tools still do not accept HEIC, and even when they do, 3 MB per photo is heavy for email or for a page on your website.
Compress in Safari with Compresso
Open compresso.space in Safari and tap the upload area. Choose Photo Library, select up to 20 photos and confirm. HEIC photos are decoded directly in your browser, turned into JPEG and compressed; PNG, JPEG and WebP images are compressed in their own format. Every result is checked against the original, and a result that would look worse is never kept.
Tap Download to save each file, or Download all for the whole batch. Safari saves the files in the Files app, in the Downloads folder, and from there you can share them or save them to Photos. Uploaded images are processed in memory and never stored.
The camera format setting
In Settings, Camera, Formats you can choose High Efficiency (HEIC, smaller files) or Most Compatible (JPEG, larger files). Most people should keep High Efficiency: it saves storage on the phone, and you can still produce a compact JPEG whenever you need to share one.
Switching to Most Compatible does not make photos smaller. It makes every photo a larger JPEG, which then needs compressing anyway.
What about the size options in Mail?
When you attach large photos in the Mail app, iOS may offer Small, Medium, Large or Actual Size. The smaller options work by reducing the pixel dimensions, which throws detail away for good and can make photos look soft on a large screen.
Compression that keeps the dimensions, like Compresso, is the better choice when the photo should still look sharp, for example on a website, in a portfolio or in print.
How much smaller will the photos get?
It depends on the photo: detailed, noisy shots shrink the most. A real iPhone HEIC photo we tested went from 1.6 MB to 856 KB as a compatible JPEG, 46 percent smaller, with no visible difference. Try your own photos: the saving is shown next to every file.