Image Resizer

Resize Images by Pixels, Percent or Centimetres

Different places ask for sizes in different units: websites in pixels, print shops in inches, and many Indian application forms in centimetres such as 3.5 × 4.5 cm. This tool handles all of them, keeps the proportions if you want, and can also hold the file under a maximum size in KB.

How to Use It

1. Choose one or more images.
2. Pick Pixels, Percentage, or Centimetres, Millimetres or Inches.
3. Enter the width, the height or both. With Keep proportions ticked, the picture is fitted inside the box without stretching.
4. For physical sizes, set the DPI (300 for print, 200 is common for forms).
5. Optionally set a maximum KB, then click Resize Images.

Centimetres, DPI and Pixels

A physical size becomes pixels through the DPI (dots per inch): pixels = centimetres ÷ 2.54 × DPI. So 3.5 × 4.5 cm at 300 DPI is 413 × 531 pixels, and at 200 DPI it is 276 × 354 pixels. JPG files saved in these modes also store the DPI, so print dialogs use the right size.

Tips

• To change the shape of a picture without squashing it, crop it first with Crop Image.
• For a smaller file without changing the size, use the Image Compressor.
• To work out the height for a given width, the Aspect Ratio Calculator helps.

Limitations

Making a small image larger cannot add detail; it will look softer. When Keep proportions is off and both sides are given, the picture is stretched to fit exactly. The result can be at most 40 megapixels, which is far more than any screen or form needs.