I'll go down to the status bar at the bottom of the Document window, and I'll click and hold on the document size information.
That's because, if you enlarge an image a lot, at some point, it can start to look blurry. In most cases, you'll want to start with an image that's bigger than or at least not a lot smaller than the resized image that you need. Before we resize this image, let's check how big it is to start with. I'd like to set the size of this image, so that it's a good fit for posting to a particular website, where I happen to know, that the ideal image size is 900 pixels wide. I suggest that you start with this image from the downloadable practice files for this tutorial. Let's talk about how to change the size of an image in Photoshop.