How to use it
- Set a quality for photos. 70 to 80 cuts size substantially with little visible change.
- Optionally set a maximum width or height. Nothing is gained by emailing a 6000-pixel photo.
- Add the images and check the percentages. Download the ones you are happy with.
The two big levers
Pixel dimensions matter most. A modern phone photo is often 4000 pixels or more across. If it will only ever be seen on a screen, 2000 pixels is plenty, and that alone removes about three quarters of the data before any compression happens. Use the maximum width or height box for this.
Quality is the second lever. JPG and WebP get small by discarding detail the eye is least likely to notice. Going from 95 to 80 often halves the file with no difference you could point to. Below about 60, you start to see blocks in smooth areas like sky and skin.
PNGs are handled differently
PNG has no quality slider because it is lossless. The way to shrink one is to reduce the number of distinct colours it uses, then let PNG's compression work on the simpler image. For screenshots, logos and illustrations, 256 colours is usually indistinguishable from the original and often less than half the size. The PNG setting here does exactly that; there is also a dedicated PNG compressor.
When the file gets bigger
If an image was already compressed harder than the settings you chose, re-encoding it can make it larger. When that happens, the tool keeps your original and tells you so, rather than handing you a worse, heavier file. Sizes are shown in KB and MB using 1024-based units, the way Windows reports them; if you need to convert between units, StatGarden has a kilobytes to megabytes calculator.
Questions people ask
How do I compress an image to under 1 MB?
For a phone photo, set the maximum size to 2000 px and quality to 75. That almost always lands well under 1 MB. For a stricter limit such as 200 KB, try 1200 px and quality 70.
Will compressing reduce the quality?
For JPG and WebP, yes, slightly. The aim is to reduce it in ways you cannot see. Compare the result with the original at 100% zoom if it matters.
Is there a limit on how many files I can compress?
No. The work is done by your own device, so the only limit is its memory. For hundreds of large photos, go in batches.
Does compressing remove EXIF data?
Yes. The image is redrawn, so camera details and GPS location are not carried over.