One post-processing trick you should know is how to resize an image in Adobe Lightroom. It’s both easy to learn and useful.
In this article, I’ll show you everything you need to know about resizing images in Lightroom.
A note before we start. I’m using Lightroom 5. If you’re using a different software version, your screen might look different. But the resizing process is the same.
What Do Pixels Have to Do With Resizing Photos
A pixel is the smallest piece of information that makes up a digital image. In fact, your photos are a lot of pixels arranged in a specific order.
When you enlarge a photo enough, you can actually see the pixels as little squares.
This image was enlarged 11 times using the zoom in Lightroom (marked with the pink arrow)
Most cameras these days capture images with a huge amount of pixels (millions!).
The number of pixels in a photo also depends on the camera model and the amount of pixels in the sensor.
Having a lot of pixels is great when you’re working with large prints. It allows you to have sharp images.
But more pixels also mean more data on the file of the photo. This causes the file size of your photos to be big.
The problem with having big files is that they make websites heavy and slow. And social media platforms don’t accept them.
You can solve this problem by resizing your images in Lightroom. But first you need to know how many pixels your image has.
How to Check Pixel Dimensions in Lightroom
Once your image is imported into Lightroom, you can check this easily. In the Library module, select the image in the Loupe mode (by clicking in its thumbnail).
If you press the shortcut “I” on your keyword, you will start a cycle of information overview. The first time you press “I”, the file name, the date and time you took the photo as well as the pixel dimensions will appear.
Pixel dimensions are shown in width and height format (white arrow in the image below).
Press ‘I” again. Now you can access to some of your image settings such as aperture, shutter speed, focal length etc.
In order to exit from the information overview, just press “I” one last time.
Resizing Photos in Lightroom – the Workflow
In Lightroom, you can resize your images when you export them. To do so, go to the Grid mode of the Library module (by pressing the shortcut “G”). Select the image or images you want to resize.
To select images, click on their thumbnail while pressing Ctrl (or Cmd if you’re using a Mac).
If the images are next to each other, click on the first one and then select the last one using Shift+Ctrl+click (Shift+Cmd+click on a Mac).
Once you have selected all the images you want to resize, open the Lightroom Export Dialog. Click on the “Export” button.
The panel shows several options for the export, including export location, file naming, metadata and watermarking. If you want, you can give your images custom names here.
Today we will focus on the “Image size” part, just under File Settings.
In this panel you can also select the resolution of your image and export it. This option does not involve resizing.
The final image will have the same amount of pixels as the original. Its size in inches/cm will depend on the resolution.
Resizing an Image in Lightroom According to Width & Height
To resize your image, you need to select the “Resize to Fit” box.
If you don’t need to enlarge the photo, check the box “Don’t enlarge” to make sure that Lightroom won’t do it. Remember that enlarging always decreases the image quality.
In the drop-down menu you can choose between several resizing options. The first one is “Weight & Height”.
Here you can choose the width (W) and height (H). In the drop-down menu you can choose to use pixels, inches or centimetres.
Lightroom will fit the photo to its dimensions as best it can. The final image might not be exactly the size you introduced.
Resizing an Image in Lightroom Using the Dimension Settings
“Dimension” is the second option in the resizing drop-down menu. It is quite similar to the Width and Height one. But this time you write down the measures of the long and short edges of your images instead of Width and Height.
This option is really useful when batch resizing landscape and portrait photos. Lightroom will ignore the width and length and instead will detect its short and long edges.
Resize to Fit the Long Edge or Short Edge
If you are concerned about the size of one of the edges in your image, the best resizing options are the Resize to Fit.
You can either resize to fit the long edge or the short edge in your image.
Input the length you need and Lightroom will calculate the other side to keep the photos proportionate.
This is the option that I use the most.
Resizing Using the Megapixels Option
This is really useful if you have a file size limitation and you don’t care much about the pixel length of the edges in your image.
This happens usually when you are submitting images to competitions or to certain websites. They’re likely to specify a size limit in their guidelines.
To use the megapixels option, you just need to write the file size you need and its resolution and Lightroom will resize it accordingly!
How to Decide on the Pixel Dimensions You Need
Now you know your resizing options, but how do you decide what pixel size you need?
Websites and social media platforms have particular image sizes. It is always a good idea to check these and resize your images accordingly.
I found it really useful to check on the web for social media cheat sheets. These collect information from the most common social media platforms.
For example, Instagram image sizes right now are 1080×1080 pixels for square photos, 1080×1350 pixels for portrait photos and 1080×566 pixels for landscape ones.
Take into account that you can’t add pixels to an image. Make sure that the new dimensions are smaller than the those of the original photo.
How to Choose the Right Resolution
Now that you know about the pixel dimensions, you need to decide on the image resolution.
Resolution is the number of pixels than an image has in a certain space. It is also known as the pixel density and it is usually measured in pixels per inch (ppi).
A 72ppi image will have 72 pixels in each inch. A 300ppi image will have 300 pixels each inch and so on.
Images with higher resolution are sharper but their files are bigger. For that reason, high resolution images are kept for printing. They are not the best option for websites and social media platforms.
So your resolution depends how you plan to use the photo: digital or print?
The Best Resolution for Digital Images
It is agreed that 72ppi is a good resolution for websites and social media photos. This is the resolution of most of screens.
It’s still a small enough resolution that websites can load the images fast and smoothly.
However, there are screens with 100ppi and even 150ppi. If you prefer to use these resolutions instead, the loading speed of your website will be slower.
It’s up to you to decide what is more important: higher resolution or higher speed.
The Best Resolution for Prints
If you are going to print your image it will need to have a higher resolution than for a website. For example, this could be 300ppi.
If you want to print your photo on a canvas, a lower resolution like 150ppi will be good enough. The pixel dimensions of your photo together with your resolution will determine the size in inches/cm of your final printed photo.
If the original photo has 4874 pixels in the long side and I want to print it at a resolution of 300 pixels per inch, doing the math will give a final print of 16.25 inches long.
Resizing is always a bit confusing at first. Luckily, Lightroom makes the process much easier!
First, you need to decide the final image size of your photo. This will vary depending whether you want to print the photo or share it in a web or social media platform.
In any case, with just a few simple steps you can resize your images in Lightroom to fit the dimensions and resolution you want.
And it’s a very fast process since you can resize multiple images at the same time too.
We have a great article on creating a Lightroom contact sheet to check out next!
A note from Josh, ExpertPhotography's Photographer-In-Chief:
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