In OpenCV, image resizing is the process of changing the size of an image. This is done by either increasing or decreasing the number of pixels in the image. The cv2.resize() function is used to perform this operation.

The function requires three parameters: the image to be resized, the desired size of the output image (specified as a tuple of width and height), and an interpolation method. Although there is a default interpolation method, specifying one explicitly can help determine how the pixel values of the new image will be computed based on those of the original image.