Example: a 12-megapixel iPhone photo
A night photo of Milan from an iPhone 12 Pro Max (public domain, Wikimedia Commons), saved as HEIC, then run through PicoDiet: full size with Original, scaled down with Auto.
What HEIC is and why it causes trouble
Since 2017, iPhones save photos as HEIC (High Efficiency Image Container), using the HEVC video codec. The files are smaller than the JPEGs older phones made, but many places still don't open them: Windows without an extra codec, many websites and upload forms, older Android phones and a lot of desktop software. People end up emailing photos that the other side can't view, or forms that reject them.
How PicoDiet compresses HEIC
PicoDiet turns each HEIC photo into a JPEG, the format every computer and website opens. It keeps the smallest JPEG that still looks the same as the original (quality score 80 by default) and checks that no small area is visibly damaged. Photos with transparency become PNG.
iPhones shoot in Display P3, a wider colour range than standard sRGB. PicoDiet keeps that colour profile in the JPEG, so reds, oranges and greens don't go dull. Camera and location data (EXIF and GPS) are removed from the JPEG, though the picture itself can still show where it was taken.
How to compress iPhone photos
- Drop your HEIC photos above, or on an iPhone tap Choose images and pick them from Photos. Up to 30 at once, each up to 25 megapixels.
- Each photo becomes a JPEG right away. Choose Auto to also scale photos down to about 1920 pixels on the long side, which is plenty for screens, email and chat.
- Compare each photo with the original, zoomed in, and download them one by one or as a ZIP.
Full size or scaled down?
A 12-megapixel iPhone photo is 4032 × 3024 pixels. Keeping full size makes sense for prints and for photos you will crop later. For sharing, email, websites and forms, Auto's 1920-pixel version is a fraction of the size and looks the same on screen: in the example above, 389 KB instead of 1.34 MB. Newer iPhones save 24- and 48-megapixel photos, where scaling down saves even more. Photos over 25 megapixels need scaling down on the phone first.
What happens to your images
Uploaded over HTTPS to the nearest of our servers, processed automatically, and deleted within 3 minutes after you finish. Never shared, sold or used for training. No account needed. Privacy policy
HEIC questions
Why does a JPEG come out of a HEIC?
Because JPEG opens everywhere and HEIC doesn't. PicoDiet never sends back a HEIC, so the file works for whoever gets it.
Is the JPEG bigger than my HEIC?
It can be. HEIC is efficient, so a full-size JPEG may come out larger than the HEIC. In our example it was smaller, 2.29 MB to 1.34 MB, and Auto took it down to 389 KB by scaling it to 1440 × 1920.
Are the iPhone colours kept?
Yes. The Display P3 colour profile is kept in the JPEG, so the photo looks the same on screens that show wide colour.
Does it work with Live Photos?
The still photo of a Live Photo is a normal HEIC and works. The short video part isn't used.
Can I use it on my iPhone?
Yes. Open picodiet.com in Safari, tap Choose images, pick photos from your library, and save the JPEGs to Files or Photos with the share button.
What about HEIF?
HEIF is the same container; .heif files from other phones and cameras work too.
Are my images private?
Yes. Images are uploaded over an encrypted connection to the nearest of our servers, optimized, and deleted within 3 minutes after you finish. They are never shared, sold or used for training, and there is no account to sign up for. Details are in the privacy policy.