In addition to resizing an image, you can also change the image size by changing the canvas size, cropping the image, or printing at a different size.
Resizing the image removes pixels to make it smaller or adds pixels to make it larger.
Increasing the canvas size adds pixels at the edge of the image. Decreasing the canvas size hides pixels at the edges of the image (full layer information is kept).
Cropping an image deletes the pixels outside the selected crop area.
Printing through Print Layout resizes the image for printing but the image file remains unchanged. This is the best option if you want to print the image at various sizes.