Three ways to resize
By pixels is what screens care about. A website slot, a social media post or an upload form usually states a size in pixels, such as 1080 × 1080. Type the width, and with the lock closed the height is worked out from the shape of your first image.
By percentage keeps the shape and scales everything at once. 50% halves both sides, which leaves a quarter of the pixels and usually cuts the file size by around 70%.
By print size is for photos you will print or documents that must be a certain size on paper. You give the size in centimetres, millimetres or inches plus a resolution in DPI (dots per inch), and the tool works out the pixels. It also writes the DPI into the JPG or PNG, so print software shows the right physical size.
Worked examples
- A 6 × 4 inch photo print at 300 DPI: 6 × 300 = 1800 and 4 × 300 = 1200, so you need 1800 × 1200 pixels. A 12-megapixel phone photo (4032 × 3024) has more than enough.
- A 35 × 45 mm passport photo at 300 DPI: 35 ÷ 25.4 × 300 = 413 and 45 ÷ 25.4 × 300 = 531, so 413 × 531 pixels.
- A website hero image: a 4032 × 3024 photo resized to 1920 pixels wide becomes 1920 × 1440. The pixel count falls from 12.2 to 2.8 million, and a typical JPG drops from about 3 MB to 150–400 KB at the default quality of 85.
Social media sizes
| Use | Size in pixels | Shape |
|---|---|---|
| Instagram square post | 1080 × 1080 | 1:1 |
| Instagram portrait post | 1080 × 1350 | 4:5 |
| Instagram or Facebook story | 1080 × 1920 | 9:16 |
| X (Twitter) header | 1500 × 500 | 3:1 |
| YouTube thumbnail | 1280 × 720 | 16:9 |
| LinkedIn profile banner | 1584 × 396 | 4:1 |
| Facebook page cover | 851 × 315 | about 2.7:1 |
Platforms crop or squash images that do not match, so the presets switch to Crop to fill: the photo is scaled until it covers the whole frame and the overflow is trimmed equally from both sides. If you would rather see the entire photo, pick Fit inside, add borders, which leaves white, black or transparent bars. Stretch forces the exact size and distorts faces, so use it only for patterns and textures. For full control over which part is kept, use Crop Image first.
Choosing a DPI
| DPI | Good for |
|---|---|
| 72–96 | Screens only; DPI has no effect on how big an image looks on a website |
| 150 | Posters and large prints viewed from a distance |
| 300 | Photo prints, brochures, passport and visa photos |
| 600 | Line art, signatures and documents you may enlarge later |
DPI on its own does not change the pixels. A 1800 × 1200 image is a 6 × 4 inch print at 300 DPI or a 12 × 8 inch print at 150 DPI. Only the print size and the DPI together decide how many pixels you need.
Tips
- Shrinking is safe; enlarging is not. Downsizing uses a high-quality filter with light sharpening, so results stay crisp. Enlarging spreads the same detail over more pixels and looks soft. Tick Don’t enlarge when batch-resizing a folder of mixed photos.
- Resize before you compress. Fewer pixels is the single biggest saving. Then use Compress Image to fine-tune quality, or Compress to KB when a form has a size limit.
- Mixed shapes in a batch. With the lock on, each photo keeps its own shape and fits inside the width and height you set. Portrait photos come out tall and landscape photos wide.
- Photos straight from a phone often store their rotation as a hidden flag. The tool applies it, so every image comes out the right way up and private details like location are removed.
- Making a document? Combine resized scans into one file with JPG to PDF.
- Photo for a passport or visa form? Check the exact size and pixel rules for each country in our passport photo size guide.