Change Image Resolution Without Changing Quality

Image Size dialog window in Photoshop

The Reality of Resizing: Changing Image Resolution without Changing Quality | Layers Magazine

Possibly one of the most confusing aspects of dealing with digital imagery is resolution-specifically, what it really is and how changing it affects an image. You’d be shocked at the number of brilliant designers who don’t know how to change an image from 72 dpi to 300 dpi-without turning it into a pile of pixel mush. That is, until now.

Today we’re going to talk about the relationship between resolution and pixels, and what it means to you. We’ll discuss the difference between upsampling-a rather evil practice of increasing the resolution (and thereby the number of pixels) in order to make the image larger than it originally was-and changing the resolution of an image without changing pixel data. First, let’s chat briefly about resolution in general.

I’ve never adequately understood this, neither to I know what it might have cost me in image quality. Good to find this resource.