# Grid-view previews slow to load



## dfkotz (Nov 16, 2020)

I keep my newer photos in subfolders of the Lightroom folder on my laptop, and my older photos (pre-2020) in a Dropbox folder.  Lightroom happily works with them all, much as when I once used multiple hard drives to hold photos.  *However,* I used Dropbox "smart sync" and most of the older photos are now cloud-only – Dropbox does not keep a local copy on my laptop.  Anticipating this, I told Lightroom to compute Standard Previews and Smart Previews for my entire photo collection.  As you know, the previews are stored in the Lightroom folder - and thus on the laptop.  

Why, then, when I open a Gallery within that old (Dropbox) folder in Grid view, does it take a long time to show the grid-view preview of the photos in that folder?  Because Dropbox is downloading all the photos so Lightroom can compute the grid-view preview.   Why is this necessary, if I already have Standard Previews?  and, for that matter, Smart Previews?  I thought the whole point of the latter is to enable me to work with photos while the underlying disk is offline.


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## Paul McFarlane (Nov 18, 2020)

What are your Standard Previews set to (size)? Generally Auto is good. By the sound of it they aren't sufficient for Lr to use. Check page 503 in your Classic book (2nd Edition) for the loading logic.

Smart Previews are used in Develop, not in Library views, unless Lr sees the photo as missing.


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## Johan Elzenga (Nov 18, 2020)

I think the answer is simple: Lightroom checks whether the file is really there, because it doesn’t understand/support the Dropbox smart sync feature, which leaves a kind of alias in your local Dropbox folder. As a result, Dropbox thinks the image is needed and so it is downloaded again.


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## dfkotz (Nov 19, 2020)

Standard Previews are set to 1440 pixels, Quality Medium.  I’ll change to Auto, Quality Medium, rebuild all the Standard Previews, and see how it goes.

I also have 1:1 previews set to discard after 1 week, but that should not affect Grid view, eh?



Paul McFarlane said:


> What are your Standard Previews set to (size)? Generally Auto is good. By the sound of it they aren't sufficient for Lr to use. Check page 503 in your Classic book (2nd Edition) for the loading logic.
> 
> Smart Previews are used in Develop, not in Library views, unless Lr sees the photo as missing.


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## dfkotz (Nov 19, 2020)

Yes, I understand that aspect, and in that regard, my Dropbox approach may be doomed; but it still begs the question: why does LR try to open the file, if it already has a preview in its cache?



Johan Elzenga said:


> I think the answer is simple: Lightroom checks whether the file is really there, because it doesn’t understand/support the Dropbox smart sync feature, which leaves a kind of alias in your local Dropbox folder. As a result, Dropbox thinks the image is needed and so it is downloaded again.


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## Jim Wilde (Nov 19, 2020)

dfkotz said:


> Yes, I understand that aspect, and in that regard, my Dropbox approach may be doomed; but it still begs the question: why does LR try to open the file, if it already has a preview in its cache?


If the Standard preview isn't large enough (and 1440 may not be, though it depends on the screen resolution), then LrC will need to build a larger one, and for that it needs the original image. It's the same if zooming to 1:1 after any 1:1 preview has been discarded.


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## dfkotz (Nov 19, 2020)

Jim Wilde said:


> If the Standard preview isn't large enough (and 1440 may not be, though it depends on the screen resolution), then LrC will need to build a larger one, and for that it needs the original image. It's the same if zooming to 1:1 after any 1:1 preview has been discarded.


Right.  I understand.  What I did not understand is that there are apparently multiple resolutions possible for a "Standard Preview" (belies the name!) and thus I've now set it to Auto per suggestion from Paul above.  We'll see if that solves it.


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## Johan Elzenga (Nov 19, 2020)

dfkotz said:


> Right.  I understand.  What I did not understand is that there are apparently multiple resolutions possible for a "Standard Preview" (belies the name!) and thus I've now set it to Auto per suggestion from Paul above.  We'll see if that solves it.


I doubt it will. I think that the problem is that the images aren’t missing. They are there, except that they aren’t really images, but Dropbox links. And that causes a problem. Lightroom may want to load the images because they seem to have changed: the file size does not match, for example. The file creation date changed too, it is now the date/time that Dropbox created the link.


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## dfkotz (Nov 19, 2020)

Johan Elzenga said:


> I doubt it will. I think that the problem is that the images aren’t missing. They are there, except that they aren’t really images, but Dropbox links. And that causes a problem. Lightroom may want to load the images because they seem to have changed: the file size does not match, for example. The file creation date changed too, it is now the date/time that Dropbox created the link.


Very possible.  I'll let you know in a week or so, after further testing with Auto size for Standard Previews.
If it does indeed work the way you describe, maybe I can convince Adobe to make LR "Dropbox-savvy".


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## Johan Elzenga (Nov 19, 2020)

dfkotz said:


> Very possible.  I'll let you know in a week or so, after further testing with Auto size for Standard Previews.
> If it does indeed work the way you describe, maybe I can convince Adobe to make LR "Dropbox-savvy".


They won’t. They’ll tell you that something like that already exists. It is called Lightroom desktop.


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## dfkotz (Nov 24, 2020)

I'm building Standard Previews ... and it's taking a long time and a lot of space.  I now consume almost half a terabyte (438GB) of my laptop hard drive just for Smart Previews and Standard Previews, the latter being (ironically) much larger.  I'm surprised the Standard Previews ( Auto size, Quality Medium) are triple the size of the Smart Previews.


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## Johan Elzenga (Nov 24, 2020)

dfkotz said:


> I'm building Standard Previews ... and it's taking a long time and a lot of space.  I now consume almost half a terabyte (438GB) of my laptop hard drive just for Smart Previews and Standard Previews, the latter being (ironically) much larger.  I'm surprised the Standard Previews ( Auto size, Quality Medium) are triple the size of the Smart Previews.


Standard-sized previews are a pyramid of jpegs at different sizes, from thumbnail to screensize. If you have a high res screen, they can become quite big. Smart previews are DNG files of only one size, 2560 pixels wide. They are around 1 MB each.


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## dfkotz (Nov 24, 2020)

Maybe I don't need "auto" standard previews ... I only want to be able to scroll through photo folders in grid view without having them appear blank or pixellated.  It's a bummer that LR requires a Standard Preview in addition to a Smart Preview, for this purpose.


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## Johan Elzenga (Nov 25, 2020)

dfkotz said:


> Maybe I don't need "auto" standard previews ... I only want to be able to scroll through photo folders in grid view without having them appear blank or pixellated.  It's a bummer that LR requires a Standard Preview in addition to a Smart Preview, for this purpose.


Lightroom does not *require* smart previews at all. Smart previews are proxies for the originals, so you can edit images when the originals are offline. They can also be used to speed up editing on slower computers. If you do not use either option, then you do not need smart previews.


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## dfkotz (Nov 25, 2020)

Johan Elzenga said:


> Lightroom does not *require* smart previews at all. Smart previews are proxies for the originals, so you can edit images when the originals are offline. They can also be used to speed up editing on slower computers. If you do not use either option, then you do not need smart previews.


Yes, I understand that about Smart Previews.  I do work offline, pretty often, so they are useful for me.    My concern in this thread is really about the Standard Previews.  Last night I dropped down a notch from Auto size previews to ~2000 pixels and that saved a lot of space.  We'll see how well they work for Grid view, my original concern.


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## dfkotz (Dec 5, 2020)

dfkotz said:


> ...  My concern in this thread is really about the Standard Previews.  Last night I dropped down a notch from Auto size previews to ~2000 pixels and that saved a lot of space.  We'll see how well they work for Grid view, my original concern.


Update, for those interested.  A week has passed.   This approach saved a lot of space, relative to 'Auto' size for Standard Previews, and has largely worked well; most of the time I can view old photos in Grid View without Dropbox needing to fetch an original to re-render a preview.   Sometimes, though, it is still necessary, implying either (a) the Standard Previews collection is aging out some photos from its cache, or (b) I happen to be viewing at a thumbnail size not available in the preview library.

Overall, I think this approach is now workable.   Would be nice to have a better approach, but as others have noted above, Adobe is unlikely to be interested in a smarter integration with Dropbox since they sell their own cloud service.

Thanks to all for the guidance.


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