Essentially, photos come in two types — high-resolution ones you print and low-resolution ones you display on the web. Image resolution is talked about in dots per inch (or dpi) and signifies the number of pixels present in one linear inch of your photo.

The type of media you use to display your dog photography images (print versus screen) dictates the necessary resolution. Web images (those displayed on a computer screen) only need a resolution of 72 dpi (referred to as screen resolution), whereas printed images need a resolution of 300 dpi (referred to as print resolution).

Have you ever printed an image off of a website, only to find that it looks like poo? That’s because the person who uploaded it to the Internet did so at web resolution.

Or conversely, have you ever visited a website and had a picture take forever to download? In this case, the person who uploaded it probably didn’t know about web resolution and instead uploaded a 300 dpi image that consequently bogs down the site.

The first thing you need to know about saving your files is that you should always save the final version of your photo at the highest resolution and in a minimally compressed file format before you do anything else. This is because you can always downsize a photo to make it smaller, but you can’t upsize a small photo to a larger size without seeing a degradation in quality.

To save a print-ready photo at 300 dpi, do the following in Photoshop:

  1. With your image open in Photoshop, go to the Photoshop toolbar and choose Image→Image Size.

    The Image Size dialog box appears.

  2. Under the Document Size section, look for the Resolution value.

    If this is already set to 300 pixels/inch, you’re good to go; just click Cancel to exit out of the Image Size dialog box.

  3. If your Resolution value says something other than 300 pixels/inch, first make sure that the Resample Image checkbox is unchecked.

    Some digital cameras record images at a setting other than 300 dpi. When you change your Resolution value from a smaller number to a larger one, you want to resize the photo without actually changing the number of pixels in the photo; that’s why you uncheck Resample Image. When Resample Image is checked, Photoshop actually changes the number of pixels that exist in the image.

    This is fine if you’re going from a larger resolution to a smaller one (for example, 300 dpi to 72 dpi) because you’re only deleting pixels that are no longer needed, but when you’re going from a smaller resolution to a larger one, Photoshop would actually be adding pixels that don’t really exist and subsequently degrading your image quality.

  4. Click OK in the Image Size dialog box.

    Your image is now correctly sized for print.