Resize Digital Photos

How to use Adobe Photoshop to resize your pictures

Knowing how to resize digital photos is one of the Photoshop essentials. It's not particularly exciting - but sooner or later we all need to do it - so you'll be pleased for having read this tutorial!

Background on how to use Adobe Photoshop to resize your pics

There are two key aspects to resizing your digital photos:

Resolution. This is a measure of image detail in pixels per inch (ppi).
Physical size. Photoshop gives you the option of working in mm, cm or inches.

As a rule you can't just arbitrarily increase the resolution of your photos, without that having a negative impact on quality.

Doing so just means asking Photoshop to conjure brand new pixels out of nowhere - roughly matching those that surround them! As you'd imagine this doesn’t do the quality much good!

But you can increase the resolution without damaging quality. Resolution and physical size have a reciprocal relationship. So by reducing the physical size of photos to account for an increase in resolution you can have smaller images with greater detail that will look better for standard sized prints.

I'll show you how to do this in the first of the Photoshop tutorials for beginners on how to resize digital photos below.

So, because - annoyingly - we can't just play around with the ppi willy nilly, that must make it tough to resize digital photos for poster sized prints without losing quality, right? Sadly, right!

But hold your horses! There is one mind-blowingly cool Photoshop trick for increasing both the size and resolution of photos in Photoshop. It breaks the rule of never asking Photoshop to ‘invent’ new pixels to match a larger sized image, which normally reduces quality.

I'll show you how to do this in the second of the Photoshop tutorials for beginners on how to resize digital photos below!

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How to use Adobe Photoshop to improve the resolution of digital photos for ordinary sized prints

Does your camera give you pictures with a low resolution? Want to create normal sized prints with excellent detail? Here's how...

Open your image in the Editor workspace of Photoshop. Press 'Ctrl + Shift + R' to make the rulers visible; these will give you a clear indication of the physical size of your picture.
Open the dialogue box that allows you to resize digital photos by going to the 'Image' menu, then choosing 'Resize' and 'Image Size'. Or just press 'Ctrl +Alt + I'.
Under the 'Document Size' heading you'll see a box that says 'Resolution'. A low resolution - like 72ppi - will produce rubbish prints. You want nice detailed ones, which need a higher resolution.

But remember what I said earlier about never just upping resolution arbitrarily? The image size has to follow suit and be decreased.

To this end, uncheck the check-box named 'Resample Image' at the bottom of the dialogue box. 'Resampling' is the word for changing the number of pixels independently of everything else.
Now enter a higher number in the ppi field. 300ppi will give you brilliant, crisp prints. As you do this Photoshop will automatically reduce the physical size of the photo which is shown in the 'width' and 'height' boxes above.

Do keep an eye on the size, since you'll know the size of print you want and don't want it to fall beneath that. If it does get too small - rein in the ppi a little bit.
Hit 'OK' and notice how your image is now measured as a smaller size by the rulers. Done!

Time for an upgrade?

How to use Adobe Photoshop to resize digital photos for poster sized prints

Got a cool shot that you'd like to make into a great big poster? Not got enough pixels to make it happen!? This is a fantastic Photoshop trick that lets you resize digital photos for poster sized prints without losing quality. (Alternatively you can use digital photo enlargement software like Genuine Fractals).

Open your image and bring up the dialogue box that allows you to resize digital photos by pressing 'Ctrl + Alt + I'.
Now - usually not to be advised - make sure the 'Resample Image' check-box at the bottom of the dialogue box is ticked.

In the 'Document Size' section of the dialogue box, enter the physical size of the poster you want to print in the height and width boxes. For example 36 x 24''.
Now increase the ppi in the resolution box to, say, 360. Usually it's best to have the 'resample image' checkbox unchecked so that the physical size of the picture scales down to match your desired higher resolution.

Not here! We need a big size and more pixels to boot. It breaks the rules but if you follow this next step you'll be amazed at the results.
In the drop-down menu adjacent to the 'resample image' checkbox, choose the 'Bicubic Sharper' option. This is the key to this Photoshop trick. Somehow it just seems to undo the damage we would expect from adding new, 'invented' pixels to a photo.

Poster sized prints look sharp and crisp when you resize digital photos with this technique!

Quotable Quote:

Oh, yes, I was a great retoucher. A retoucher is an aesthetic surgeon !

Man Ray

I often need to resize a group of images in one go. But working through them all individually is painfully boring! Luckily, there's a cool Photoshop trick that lets you resize digital photos in a large batch in a matter of seconds. Here is my tutorial on how to use Adobe Photoshop for resizing a batch of images.

Check out these Photoshop tutorials for beginners at Photography Art Cafe: Enhance your portraits, how to use Adobe Photoshop to make objects disappear, Photoshop trick for cool selective colouring.