Batch Resize Images

What this tool does

Resizes many images at once with the same rule and saves them in one format. Useful for preparing training datasets or unifying product photos.

Steps

1. Upload several images.
2. Choose the method. For "By one side" set the base side and length; for "Fixed size" set the width, height and how to handle a differing ratio.
3. Set the output format (and quality for JPG/WebP) and the naming.
4. Press "Start". When it finishes the results appear in the list.
5. Save everything at once with "Download all as ZIP", or send to the workbench.

Settings

• By one side: matches one of long side, short side, width or height to the set length and sets the rest by ratio. With "Do not enlarge small images" on, images smaller than the base stay as they are.
• Fixed size: makes every image the set width x height. If the ratio differs choose Padding (everything shows and leftover is filled with a color), Center crop (fills fully and cuts the overflow) or Stretch (ignore the ratio).
• Padding color: the color of leftover space for padding (shown only in the fixed size method). Saving as JPG fills transparent parts with this color too, and with the By one side method the color last set (black at first) is used.
• File names: keep the original name (only the extension changes) or number 0001, 0002.

How it works

It reads each image, redraws it at the size from the settings and encodes it in the chosen format. When shrinking a lot it shrinks in steps to keep sharpness. If one file fails the rest continue, and when done it reports the success and failure counts.

Good to know

• A GIF is processed using its first frame only. To resize an animated GIF use the Trim and Resize GIF tool.
• After uploading you cannot add more images. Use "Clear list" and upload again from the start.
• If a result name already exists a number is appended. The ZIP is named resized.zip.
• Results are gone when you close the tab.