Does the image upload to a server?

No. The file is decoded, scanned, cropped, and exported in the browser.

How is the crop box detected?

The tool scans the alpha channel and finds the top, right, bottom, and left visible pixels.

Requested padding is capped to the largest uniform padding available inside the original image.

Remove transparent padding from PNG, WebP, AVIF, or GIF images. Auto-crop to visible pixels, add padding, and export a square PNG in your browser.

How is the element detected?

The tool scans alpha values and finds the tightest rectangle that contains visible pixels.

Why can the output have extra space on one axis?

Rectangular elements need transparent fill on the shorter side to produce a 1:1 PNG.

What if padding is larger than the original margin?

The padding is capped to the largest same-value margin available around the element.