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elianoimperato
elianoimperato
Known Participant
April 6, 2026
Question

Minimal previews on import

  • April 6, 2026
  • 2 replies
  • 75 views

Hi,

after Camera Bits decided to discontinue Photo Mechanic Plus I decided to build my archive with LrC. To not take more space I thought to import all my photos using the minimal previews size.

When I tried to find some photos without the hard drive connected to the computer I found a lot of empty previews:

Did LrC built the minimal previews or not?

I read that LrC generate every time the previews when you’re looking at the library, but when we’re importing and we’re waiting all that time is not generating the previews? If I’ve thousand of photos I can’t look at all the library to be sure that LrC will generate the previews.

    2 replies

    Jim Wilde
    Community Expert
    Jim WildeCommunity Expert
    Community Expert
    April 7, 2026

    Did LrC built the minimal previews or not?

     

    If should have done. After the import was completed was the grid populated with previews or blanks?

    Assuming you did see the previews, then they should still be available even when the image is offline. The only wrinkle is that, IIRC, minimal previews are meant to be automatically and silently replaced with Standard previews, but I’m not certain how that procedure would work if the volume is taken offline before the Standard preview is built. I can try to do some testing of that, but in the meantime you could consider using the “Embedded Preview” option during import (which uses the camera-embedded jpeg). I use that all the time, it gives more or less the same view that you would have got using Photo Mechanic.

    elianoimperato
    elianoimperatoAuthor
    Known Participant
    April 7, 2026

    After the import was completed the grid was populated with previews but I couldn't check all the files I’ve imported. Also if LrC will automatically replace the “minimal previews” with the “Standard” there’s no reason we can't see the minimal? For what I waited when I’ve imported the photos? Why LrC give me the choice to use the “minimal previews” if I can’t see them later?

    I didn’t want to use the “Embedded Preview” because the minimal previews are taking less space. Unfortunately LrC save the embedded jpg generated by the camera but doesn’t has the possibility, like Photo Mechanic Plus had, to choose the size of the previews (I used 1680px).

    In any case, I can’t rebuild the previews using the “Embedded Preview” option for all the thousands of photos I’ve already imported.

    Anshul_Saini
    Community Manager
    Anshul_SainiCommunity Manager
    Community Manager
    May 4, 2026

    Hi ​@elianoimperato,

     

    Thanks for the details. Based on what Ian & Jim Wilde said, if the previews were actually built, they should still be available when the source drive is offline.

    A couple of points:

    • Minimal previews are fine for import speed, but they are not the best option if you need reliable offline viewing later.
    • For offline access, Smart Previews are the safer choice.
    • If the grid showed empty boxes after import, that usually means the previews may not have finished building before the source was disconnected.
     

    Regarding your concerns:

    "I can't rebuild previews for thousands of photos."  
    They actually can; the bulk Smart Preview build via Library >  Previews > Build Smart Previews handles thousands of photos. With LrC 15.x's GPU-accelerated preview generation is much more practical now.


    "Minimal previews take less space"

    Smart Previews are small, too. For 10,000 photos, that's roughly 10-20 GB, probably a worthwhile tradeoff for full offline access and editing capability.


    "Photo Mechanic let me choose preview size (e.g., 1680px)"
    LrC doesn't offer that level of granularity for the minimal preview, but the Standard Preview size is configurable in Catalog Settings > Previews > Preview Cache > Standard Preview Size (options: 1024, 1440, 1680, 2048, 2880 px).


    "Why does LrC offer Minimal if they're unreliable?" 
    Minimal previews are intended for the fastest possible import when you plan to stay online and browse immediately. They were never designed for persistent offline access; that's Smart Previews' job.

     

    So the main test is:

    • Leave the source drive connected after import
    • Give Lightroom Classic time to finish building previews
    • Then check whether the thumbnails are visible before taking the drive offline

     

    If offline viewing is your priority, I would recommend using Smart Previews instead of Minimal Previews.

     

    Regards,
    Anshul Saini

      Conrad_C
      Community Expert
      Conrad_CCommunity Expert
      Community Expert
      April 7, 2026

      If you want previews to be available when the volume containing the source is offline, generate Smart Previews for those images. I am not sure if normal previews are supposed to be available when the source’s volume is offline. 

      Ian Lyons
      Community Expert
      Ian LyonsCommunity Expert
      Community Expert
      April 7, 2026

      ​@Conrad_C 

       

      If the previews were built, then they should be available when the originals are offline. 

       

      Regarding the OPs issue, I suspect that he did not give sufficient time for the previews to be built after importing use ng Minimal previews.

        elianoimperato
        elianoimperatoAuthor
        Known Participant
        April 7, 2026

        Exactly, if I waited during the import process because LrC was building the previews I should see them also if the files are offline.

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