Lightroom Tips

How Much Space Do Lightroom Smart Previews Really Take Up?

Starting in Lightroom 5, Adobe released something called a Smart Preview. It’s basically a preview of your photo, that’s big enough to let you work on your photos even if the drive they’re on isn’t connected. Here’s a screenshot of the option in the Import dialog.


It’s a great option for people who like to stay mobile because they don’t always need to keep their external drives with them. So what’s the tradeoff? Why not build a Smart Preview for everything? Well, they take up space on your computer’s hard drive (or whatever drive has your Lightroom catalog on it). But how much space? Well, after running some tests, I’ve found that it’ll roughly take up anywhere from 2-5% of the actual photos themselves. So, for example. If you’re uploading 1 GB of photos and you choose the Smart Previews option, you’ll have a file called “YourCatalogName Smart Previews.LRData” that’s about 25-50 Mb in size.

How To Delete Smart Previews
A good practice to get in to is this. Let’s say you’re working on a photo shoot and you want access to work on it even if the drive the photos are on isn’t connected. Well, building Smart Previews would be a great option. But then let’s say you’re done working on that shoot after a few days and don’t need the Smart Previews anymore. Well, you can just go to the top menu (in the Library module) and go to Library > Previews > Discard Smart Previews.




  1. Tony Arroyo 28 January, 2016 at 07:15 Reply

    Hi Matt,
    Quick question.
    I have my LR catalog stored/saved on my external drive alongside my pictures. My problem is that when I create smart previews it creates them on the external drive with the catalog, so when I detach the external drive I can’t view my smart previews.

    My question is, can I drag my smart previews folder from the external drive to the internal one, and if so, once I reboot LR will I see the smart previews with the external drive detached?

    • Eyewanders 26 September, 2016 at 02:59 Reply

      If you store you LR catalog on the external drive, what reason would you have to move the smart previews to the internal drive since you cannot open the catalog without having the external one connected? That don’t make no sense. 🙂
      If you’d like to be able to utilize smart previews as intended, move your catalog and lrdata folder info to the internal drive *separate* from where your photos are stored.

  2. Erick 7 January, 2016 at 17:10 Reply

    Thanks for the tips! I created a new Catalog with about 5.5 Gigs of photos that are stored on an external hard drive. Upon importing the photos I checked the “Build Smart Previews” box and everything seemed to work well. My issue is that when I whet to see how large the Smart Preview.lrdata file was on my local hard drive I discovered that it was 3.5 gigs. As you can see, this won’t save me much space. Am I doing something wrong? I even delete all the Smart Preview, as per your instructions, and re-built the Smart Preview. That didn’t work either.


    • Craig Volpe 25 April, 2017 at 15:11 Reply

      That seems strange but it could have to do with the size and format of the original files. Are they relatively small JPGs? Smart Previews wouldn’t be that much smaller than the originals in that case.

  3. AL 13 May, 2015 at 13:39 Reply

    So, I’ve been using Smart Previews for a while no, having no problem. The other day, I decided to go through my old backup catalogs and delete the less recent ones, and leave the files of Smart Previews. Today, when I restarted Lightroom, it looks like the latest catalog dose not recognize that most of the files have Smart Previews, so most of my library is showing up blank. Do you know how I could re-integrate the existing Smart Previews into my current catalog, or otherwise import the existing Smart Previews? Hope this is a clear description! Thanks

  4. The Andrew S Gibson photography blog » Blog Archive A Short Guide to Using Smart Previews in Lightroom 5 » The Andrew S Gibson photography blog 14 January, 2015 at 18:41 Reply

    […] Smart Previews are tiny. I exported the original Raw files contained this small Catalog (16 in total) and the total file size was 430Mb. The size of the Smart Previews file is only 9.1Mb. The Smart Previews file is only a little over 2% the size of the Raw files (corresponding with Matt Kloskowski’s findings). […]

  5. Dennis 15 August, 2014 at 02:31 Reply


    Yesterday I have been generating Smart Previews with Lightroom 5.6 on my MacBook Pro running OS X 10.9.3 in order to save space on my SSD. My RAW’s are stored on an external drive.

    Everythings works fine. When I disconnect the external drive, only the smart previews are used.

    What I noticed is that of my 200GB+ RAW files the Smart Preview file remains about 300MB in size. I only have one catalog and when searching I only find one Smart Preview file, the one in the same folder as the catalog file. When I look at my catalog configuration I see that calculated Smart Preview file size is much lager than the 300MB.

    Do you have any idea what’s going on here?

    With kind regards, Dennis

    • Craig Volpe 25 April, 2017 at 15:13 Reply

      I’m not sure why, but Finder sometimes doesn’t show the correct size of the Smart Previews file. Finder reported mine as 9 GB, but when I copied it to another drive it was actually 121 GB!

  6. Pieter-Jan 1 May, 2014 at 06:56 Reply

    I’m testing this whole Smart preview thing, but one thing I came across..
    I have around 400GB on images, so if I would make a smart preview of all of them, it will result in a file of 20gig or something > perfect for a laptop with SSD! Right?

    I tried this with 20 pictures, everything works out well, but then, if I permanently delete the 20 pictures from my hard drive (external), the smart preview file stays the same size.
    So my guess is that the real pictures are deleted, but not the smart previews… so in time, the smart preview file will become bigger and bigger, since everything stays on it.

    A solution to this might be that before you delete pictures, you always delete the smart previews first, but that’s kind of annoying…
    So my question is: is there a better solution to this problem?


    • Pieter-Jan 1 May, 2014 at 08:26 Reply

      Meanwhile, I already found the answer:
      If you “optimize catalog” then the smart previews of deleted pictures are removed 🙂

  7. Spike 2 March, 2014 at 13:54 Reply

    Is there any way to selectively delete Smart Previews? I have this problem of creeping disk storage for Smart Previews, but sometimes need one shoot and don’t need others any more.

  8. Dennis Zito 25 February, 2014 at 08:18 Reply

    Thanks for this tip, Matt! Since LR 5 came out I’ve wondered how big the file space would be and how to get rid of them! My 15 inch Macbook Pro retina has a 250 GB ssd in it. So I only have my programs installed on it. I use a 1tb G drive to store my vacation photos and photowalk photos. So, I would save my photos on the G drive and then wait to get home before processing them on my Desktop. So my question is if the Smart Previews are stored on the Laptop how do I get the changes I’ve made to them to my desktop? As you can see I’m not a great computer wizard! 🙂



      • Shirley in NJ 8 March, 2014 at 00:50 Reply

        OK, I’m clearly less of a “computer dude” than Dennis. What I don’t understand about your answer to him is …

        His program is on his laptop; his photos on his external drive; and, his concern is how to get his smart previews onto his DESKtop.
        He assumed his smart previews are on his LAPTOP (not his external hard drive). Am I correct in understanding that to be wrong?
        Do the smart previews attach themselves to the photo (like an xml file)? Is that what you meant by it would automatically sync (cuz the necessary file/info stays with the photo, not on his laptop where the program is)?
        I’m just wanting to be sure I’m understanding since this is a question I also needed an answer to!
        Thank you!

        • Eyewanders 26 September, 2016 at 02:55 Reply

          The smart previews do not “attach” to anything. They are created in a separate lrdata folder that exists in the same folder location that you chose for lightroom catalog.

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