Smaller images load faster and fit upload limits. You can usually cut a photo to a fraction of its size with no change you can see, if you do it in the right order.
Step 1: make it the size you need
Most of a photo file is pixels you do not use. A 4000 × 3000 photo shown at 1200 pixels wide carries about eleven times more pixels than it needs. Resizing to the size you will actually show is the biggest saving.
Step 2: choose the right format
- Photos compress best as WebP or JPG.
- PNG does not shrink with a quality slider, so switch a photo from PNG to WebP or JPG.
- Keep PNG for logos, text and transparency.
Step 3: lower the quality a little
For photos, 75 to 85 percent usually looks the same as the original on a normal screen. Below about 60 percent, blocky patches start to show in smooth areas such as skies.
Step 4: set a target size if you have a limit
If a form says the file must be under 200 KB, enter that as the maximum size. The tool tries different quality levels and keeps the best one that fits. If quality alone is not enough, it also reduces the dimensions a little at a time.
What to avoid
- Saving a JPG again and again. Each save at low quality adds more blockiness. Keep your original.
- Enlarging a small image. It makes the file bigger without adding detail.