Example: an 11-megapixel camera photo
A 3719 × 3056 harbour photo from a Sony DSLR (public domain, Wikimedia Commons), with PicoDiet's default settings. At score 90 it was 3.03 MB, at 70 it was 248 KB.
Why JPEG files are bigger than they need to be
Cameras and phones save JPEGs at a high quality because they can't know how the photo will be used. Much of that data is invisible at normal viewing size, like fine noise in a blue sky or a blurred background. So photos come out at 3 to 10 MB, upload slowly, hit email limits and slow web pages down.
Re-saving at a lower fixed quality helps, but no single number suits every photo. In our tests, four photos saved at JPEG quality 75 scored from 71 to 75, a little under what looks the same, and each needed a different setting to reach 80. How quality is measured has the numbers.
How PicoDiet compresses JPEG
PicoDiet tries several quality levels for each photo, scores how close each one looks to your original, and keeps the smallest JPEG that still scores at least 80, or the score you choose. It also checks that no small area, like a face, a sign or a line of text, is visibly damaged. How the score works
You get a standard JPEG that opens everywhere. Camera and location data (EXIF and GPS) are removed; the colour profile is kept, so wide-gamut photos keep their colours.
How to compress a JPG
- Drop your JPG or JPEG files above or choose them; up to 30 at a time, each up to 25 megapixels.
- Each photo is compressed right away. Raise the quality for prints or photos you will edit again; lower it for thumbnails.
- Open a photo to compare it with the original, zoomed in where it changed most, then download it or all of them as a ZIP.
Make photos even smaller: resize
A 12- or 24-megapixel photo has far more pixels than a screen shows. For the web, email or chat, Auto scales photos down to about 1920 pixels on the long side (never under 1080 on the short side) as well as compressing them; the 4.97 MB harbour photo above becomes a 1920 × 1578 JPEG of 144 KB, 97% smaller, still at score 80. You can also choose an exact maximum size under Options.
What the quality setting means
| Score | What you see | Harbour photo |
|---|---|---|
| 90 | No visible difference at normal size | 3.03 MB (−39%) |
| 80 | The same at normal viewing size | 666 KB (−87%) |
| 70 | Small artifacts in smooth areas up close | 248 KB (−95%) |
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
JPEG questions
Is JPG the same as JPEG?
Yes. JPG and JPEG are two file extensions for the same format; early Windows allowed only three letters. PicoDiet keeps the extension your file had.
Does compressing a JPEG again lose quality?
Every lossy re-save changes the image a little. PicoDiet measures the result against your original and only keeps it if it scores at least your setting, so the loss stays below what you can see at normal size. If it can't make the file smaller without going under, it keeps the original.
Why is my JPEG barely smaller?
It was probably already saved at a low quality, for example by a messaging app or a website. There is little left to remove without visible damage.
Can I compress a JPEG to a specific size, like 100 KB?
Yes. Switch from Quality to File size above the results and pick a size, or open compress to 100 KB: PicoDiet keeps the best-looking JPEG that fits, lowering the quality first and the dimensions only if it has to. Reduce image size in KB lists every preset.
Does it keep the photo's colours and orientation?
Yes. The colour profile is kept, and photos come out upright as your phone shows them.
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.