Choosing a resampling method

Resizing bitmap images always presents a unique problem—do you add or remove pixels to resize the image, or do you change the number of pixels per inch or centimeter?

You can adjust the size of a pixelated image in these ways:

Original and after downsampling an image
 

	Adjust the resolution, which changes the size of the pixels in the image so that more or fewer pixels fit in a given space.
	Resample the image.
	When you resample an image, pixels must be added or removed to make the bitmap larger or smaller. Either way, the image is altered, which can result in some quality loss at the target resolution.
	Downsampling, or removing pixels to make the image smaller, always causes quality loss because pixels are discarded to resize the image.
	Resampling up, or adding pixels to make the image larger, may result in quality loss because some pixels are being added to make the image larger, and the pixels that are added do not always correspond pixel-for-pixel to the original image.
	Original and after downsampling an image