FormatFoxWhere the slider earns its place
Photographs of scenes, faces and landscapes take heavy compression well. Dropping quality noticeably can halve a file again after a resize, and on a screen the difference is hard to point at.
How to compress photos on iPhone
There are only two levers that make a photo smaller, and people usually pull the wrong one. Here is which is which, and how far each one gets you.
Resizing is free in FormatFox. The quality slider is part of the one time Pro unlock.
Lever one: fewer pixels
A modern iPhone photograph is around 4000 pixels along its longest side. A mail attachment, a forum post or a form upload almost never needs that. Halving the longest side cuts the pixel count to a quarter, and the file follows it down steeply.
| Longest side | Good enough for | Not good enough for |
|---|---|---|
| 4032 original | Printing, archiving, cropping in hard later | Mail, chat, upload forms |
| 2048 | Any screen, most upload forms, a full page print | Large format printing |
| 1600 | Mail attachments, documents, web pages | Anything you will crop into afterwards |
| 800 | Avatars, thumbnails, chat | Reading small print on a photographed document |
The mechanics of that resize, including why a resized photo never comes out sideways, are on the resize an image page.
Lever two: harder compression
JPG, HEIC and WebP all throw information away to get small. How much they throw away is a number between roughly 0.3 and 1, and FormatFox exposes it as a slider once Pro is unlocked. PNG has no such dial, because PNG is lossless by design.
Where it does not
Screenshots, drawings and photographed text with fine print get visibly mushy long before they get usefully small. Resize those, or send them as PNG and accept the size.
Getting under a mail limit, in order
- Note the limit you are fighting. Mail providers commonly stop at around 25 MB for the whole message, and upload forms are often far stricter.
- Load the photos into FormatFox and set Resize so the longest side is 1600 or 2048. This alone clears most limits.
- Convert, then read the size line. It shows the real before and after byte count for each file and for the batch, so you are measuring rather than hoping.
- Still too big? Pull the quality slider down and convert again. Two passes are usually enough for even the heaviest camera output.
One thing to avoid. Do not compress an already compressed JPG over and over. Each pass decodes and re encodes the picture, and the damage accumulates. Go back to the original photo and do it once.
The reason not to use a website for this
Photos that need compressing are often photos of something: a payslip for a landlord, a signed page for an employer, an insurance claim. A browser based compressor has to take that picture onto a server before it can hand it back smaller.
FormatFox does the decode and the re encode with the image library on your phone. Nothing is sent, so nothing has to be trusted, and the whole thing works with the network off. More on that in converting files without uploading them.
Questions people ask
What is the fastest way to make an iPhone photo smaller?
Reduce the pixels. A photo scaled so its longest side is 1600 pixels is a fraction of the bytes of the same photo at 4032 pixels, and on a phone screen or in a mail nobody sees the difference. Quality compression is the second lever and matters most once the pixel count is already sensible.
Does converting HEIC to JPG make a photo smaller?
Usually the opposite. HEIC is already an efficient format, so the JPG version of the same picture is often larger. Convert to JPG for compatibility, and resize or compress separately if size is what you are after.
Is compression in FormatFox free?
Resizing is free, and for most oversized photos that is the lever that does the work. The quality slider that sets how hard JPG, HEIC and WebP are compressed is part of the one time Pro unlock, which has a base price of 4.99 EUR.
Will compressing a photo remove the location data?
In FormatFox that is a separate switch. Keep EXIF metadata copies EXIF, GPS, TIFF and IPTC information into the output, and it is a Pro control. With it off, the smaller file also carries less about where and when the picture was taken.
Keep reading
- Resize an image on iPhonePixels are not bytes. How to set the longest side of a photo and keep it the right way up.
- Audio converter for iPhoneM4A, WAV, AIFF and CAF on device, what the encoder settings are, and why MP3 goes in but never comes out.
- Convert files without uploading themWhat a browser converter has to do with your file, what FormatFox does instead, and the one thing that does use the network.
Make the file fit, on the phone