Using Image Size in Photoshop

With your image open in Photoshop, go to the Image menu and select “Image Size”.  This will open up the following window:

The “Pixel Dimensions” section changes the size of the image in relation to your computer screen.  Unless you are preparing your photos for printing, you’ll only need to adjust the pixel dimensions.  The “Document Size” section tells you how big your image is “in real life” and its resolution.  A high resolution takes up more space than a lower resolution image of the same dimensions, so this is the first thing we’ll change. 

Viva Resolution!

First, deselect the “Resample Image” check box at the bottom of the window.  Then enter either 72 or 150 for the resolution.

Once you have changed the resolution, click “OK” to close the window. 

Changing the Pixel Dimensions (a.k.a. Resampling Your Image)

Now go back to the Image menu and reopen the Image Size window - yes, the very same window I just told you to close!  This time, check the “Resample Image” box and use the pull-down menu to select “Bicubic Sharper”.  You can now edit the pixel dimensions of your image in the top section of the window. 

I usually use 900 pixels as the largest dimension for my photos, but there are a lot of factors that affect how big a digital image looks on the computer screen.  There are many different monitor resolutions that people use, anywhere for 800x600 pixels to 1440x900 pixels.  Obviously, a 900 pixel wide image will not seem as large on a larger resolution monitor as it will on a 800x600 resolution monitor.  People may even complain that your pictures are too big, even though you think they look like thumbnails on your home computer!  Generally, 900 to 1200 pixels is a good size for your “full size” webpage photos.   And for thumbnails, I use 100 or 200 pixels as the largest dimension. 

Remember, you want your photos to be big enough to show detail, but not so big that you have to scroll to see the overall image.   For “detail shots”, the crop tool is very useful - we'll talk about that in the next section.

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