An image resizer changes how many pixels an image has. This one lets you set the new size in pixels, as a percentage, or as a print size in centimetres, millimetres or inches at a DPI you choose. For print sizes the tool works out the pixels for you: a 35 × 45 mm passport photo at 300 DPI becomes 413 × 531 px. The DPI is also written into JPG and PNG files so they print at the intended size.
With the aspect ratio locked, change the width and the height follows, so nothing is distorted. Unlock it, or pick a preset such as Instagram post (1080 × 1080), story (1080 × 1920), YouTube thumbnail (1280 × 720) or LinkedIn banner (1584 × 396), and choose what happens when the shape changes: crop to fill, fit inside with white, black or transparent borders, or stretch. A live preview of the first image shows the result before you spend a run.
Resizing in batches works too: with the lock on, each image keeps its own shape inside the size you set, and you can skip enlarging images that are already small. Honest limits: enlarging adds pixels but not detail, so upscaled images look soft, and very large outputs (above about 16 megapixels or 16,384 px a side) are refused because browsers can't hold them. EXIF data is not copied to the resized file.
