How to batch resize in Lightroom

A commonly asked question by the readers of this blog is – how do I batch resize in Lightroom?

As I have been with Lightroom since version 1.0, here are my tips for you, along with a bit of background information you might find useful.

1. Lightroom was not really made to “batch resize”

The typical workflow with Lightroom is to import the image files from disk or device, to make changes to them using Lightroom’s “Develop” mode, and then to export the finished photos into the desired format. It’s very simple: Import – modify – export. To understand this will help you to make best use of Lightroom, especially when working with RAW files.

During import, Lightroom copies the original files to the disk, but leaves them untouched during post processing. When you make changes to an image, the program remembers these changes in a separate file, so that you can always start over again with the original file should things really go wrong. When you are done with your post processing, Lightroom takes the original files and applies all the modifications you did to a copy of the file, and then saves this copy to a location specified by you. One of the export options is to specify a certain image size, so the image will be saved as a scaled down version. This resizing is really just the last step in a series of steps.

You see: the logic behind Lightroom makes it not the perfect batch resizing tool. But having said that, I also have to admit:

2. Lightroom still can do the job of “batch resizing”

2.1 How to use Lightroom to create a set of images that is smaller in size

And it’s rather easy now that you know how Lightroom works. If all you want to do is to scale down a bunch of JPEGs, then:

  • Import them from device or disk
    File > Import Photos from Disk…
  • In Library Mode, mark all of the imported photos
    Edit > Select All
  • Export them to the desired size
    File > Export…

In the Export dialogue, you can specify the Export Location, the output format and output quality (in case of JPEGs), the color space and the resizing options. And you are done.

2.2 How to use Lightroom to create a set of images that has a specific aspect ratio

If you have a certain set of images that you want to constraint to a certain size, this can be done with Lightroom by synchronizing the Crop Overlay:

  • Import the photos from device or disk
    File > Import Photos from Disk…
  • Select the first photo of the set, and go to Library Mode
  • Activate the Crop Overlay
  • Select the desired aspect ratio from the drop down menu, e.g. 4×6
  • Move the crop overlay to the desired location (optional)
  • In the film strip below the main window, mark all the other images where this aspect ratio shall be used (Lightroom will safely work with mixed image orientations, i.e. upright and panorama shots can be selected at the same time)
  • Click the “Sync…” button at the right bottom
  • In the “Synchronize Settings” window, activate “Aspect Ratio”, plus all the other settings you may want to copy from the first photo to all selected photos
  • Click the “Synchronize”button
  • For each image, check whether the Crop Overlay is indeed at the correct position, ensuring that no important parts of the image are chopped off (optional)
  • Export the selected images to the desired size
    File > Export…

And you are done.

9 Responses to “How to batch resize in Lightroom”

  1. Kendall Lister says:

    This isn’t exactly the same, but I just discovered that the “Copy”/”Paste” and “Synchronise” functions in the Develop module work for crops, allowing me to quickly create, say, square versions of a whole set of photos. I did this manually a few months ago and it was very painful, since I had to change the crop aspect ratio for every single photo. The Synchronise function will let me apply a 5 x 7 ratio crop to a whole album to make it ready for printing.

    It seems to me that “resizing” isn’t really a photo development operation, in the same way that setting resolution wouldn’t be a page design and layout operation, but merely something to be done prior to printing or rendering into a particular format. I find it easier to imagine that my photos aren’t in any particular “format” when they are in Lightroom, but that I can specify any format/resolution (size) when I export them. Lightroom isn’t the final destination for these photos, so it doesn’t make sense for me to think of them as having a size (in pixels).

  2. admin says:

    Hi Kendall, thanks for your comment. It never occured to me that cropping is also a way of “resizing” an image. But your comment sheds light on this area as well, much appreciated.
    I also agree that “resizing” is not a photo development operation. I guess that many photographers are looking into Lightroom (never bothering to RTFM) and are now puzzled how to get even the most basic steps done, e.g. batch resizing. Many probably still think this tool is more like ACD See which has a specifc command for this.
    You are absolutely right that Lightroom is a photo development platform, including a storage solution, that holds the images and not some specific representation of these images, e.g. 5″x7″ JPEGs in sRGB at 250 dpi. And certainly Lightroom is not the final destination. Hopefully.

  3. professor_p says:

    interesting comments…i too was looking for an answer to the question of renaming/sizing large numbers of files in lightroom, knowing it is not made for that…as stated it can be done, however, when you use the export command there is a box to tick to resize but it does not appear to have that all important function of aspect ratio…so you can change to dpi and quality and name…if i have missed something about aspect ratio, please post…if i want to batch, i use canon dpp, it makes batching a breeze, only you can not batch raw files, so it kind of defeats the purpose if you want to functions of photo processing that lightroom is never easy is it!

  4. Mark Zanzig says:

    professor_p: I don’t think you can use the Lightroom Export dialogue to resize to a certain aspect ratio, say 16:9. The reason seems to me that there may be images that do not fit into the desired format. To make such images fit, the software would have to cut off parts of the image. (I agree, they could’ve implemented a function “crop image to make it fit into aspect ratio” for Export.)
    Cropping -as it is now implemented- happens only in the Develop module. You can synchronize image croppings, but you have to do it in Develop as laid out above.

  5. Janna says:

    I want to do a similar thing – but perhaps the opposite example. I have odd shaped sized photos (e.g. square or extra tall) that I want to print on 4×6 without cropping any of the photo out, and just having black or white or filler on the “extra” paper. For example, a square photo would print the photo on 4×4 of the 4×6 paper, and there would be 2 inches of just black on one side, or one inch on either side, etc. I haven’t found a way to do this yet. If there is any answer to this dilemma using any tool I would love to know! Too bad the family photos from the early 1900′s didn’t come in today’s aspect ratios!

  6. Mark Zanzig says:

    Janna: Yep, Lightroom seems to lack this capability. The closest that LR gets is in the Print Module where you get exactly this feature, and implemented in a good way. But there seems to be no way to get the image out as plain TIFF or JPEG. All it offers is to send the document to the printer.
    If you want to send the files to the lab, I suggest to use Photoshop CS3 to adjust the Canvas of each image. Maybe you can record an Action to (mostly) automate this?

  7. Cyd says:

    I need to batch process a group of photos and also resize them, but by resize what I mean is something a little different, I hope you can help.

    I am creating a photo catalog of images of an artifact, in this case a boat. There are probably 500 images in all. Each photo was taken in the same lighting, with the same lens, and from approximately the same distance, but not exactly the same distance. There is a scale in each photo attached to the boat. What I need to do, is to create finished photos in which that scale is exactly the same size in each one.

    The graphic artist that I consulted with did not have a solution for me. I’m using Lightroom to edit and enhance the detail in the raw images, but also have CS6 if Photoshop would be the more appropriate tool for this.

    Is it possible to get the desired results?? Any help is much appreciated!

  8. Mark Zanzig says:

    Hi Cyd, what an unusual problem.

    I do not think that you can tackle this with Lightroom. Two reasons: First, you can not specify individual enlargement factors per image as Lightroom defines the final size and resolution at export time. Second, in Lightroom, you
    can not easily measure the amount of reduction (or enlargement) required.

    Here is how I would approach this task: Use Photoshop. Measure the length of the scale in each image and then calculate the required reduction or enlargement (as percentage) and apply it to the image in the resizing dialogue box. To help with this, I’d create a tiny Excel sheet to collect the measurements of the scale in each original (to measure the length, open the “Info” palette, where you can see the length of a line drawn while it is drawn). When you are done with the data collection, you can then specify the desired target length (i.e. how long the scale should be in the resized images), and Excel can calculate the percentage for you that needs to be entered in the resizing dialogue (the formula is target size/measured size x 100). Then save the image using another name (to keep the original file intact). The result will be that the scale has the same length (in Pixels) in each image.

    One more thought: You probably do not want to ENLARGE your photos as this means a potential loss of quality. So, the desired target size is effectively limited by the scale with the shortest length in the original image. This image will not be resized but act as a “reference” instead. To find that image, you can add a MINIMUM function in the column below the measurements. This value will be the perfect target size.

  9. Keeby says:

    Thanks this really helped.

    I wanted to resize multiple images / photos.

    Go to ‘edit’ and then ‘select all’… or select only some of the images by clicking on them whilst holding ‘ctrl’. Then go to ‘file’, ‘export’… seems simple and kind of obvious now… and choose the desired location to save and which size to scale to etc.