Best preview size for large JPG library? (Classic)

[Cwarim]

Hi all,

I have a set of about 80,000 jpgs that I want to put into a new catalogue for organisation. These photos are on an external hard drive (not an SSD). About half are 3000x2000, the rest smaller. I'm on a 2018 Macbook Pro.

I will not be developing these photos - this is simply a culling and keywording exercise.

Anyway, I have already tried this once, and chose "embedded" as the preview size since I really don't feel like I need standard or 1x1 previews for what should be easily loadable jpgs. However this appears to have resulted in about 60GB of previews being created - exactly what I was trying to avoid. If I can keep the preview file size down I can leave the catalogue on my laptop's fast SSD. Otherwise it needs to go to the external drive. More frustratingly, I have also been getting a ton of loading problems where Lightroom appears to not be able to find 3 to 10 photos in a folder it is otherwise already accessing just fine.

So... what's the best preview option when dealing purely with JPGs and never developing? Is lightroom going to be building previews of each JPG I look at in loupe view anyway? Is that what is inflating the preview file size? Will the catalogue work okay if I use minimal previews or will that create performance issues?

[JohanElzenga]

If you use 'Embedded & Sidecar' and you do not want Lightroom to generate previews, then make sure you deselect the option in the Lightroom preferences. I'm not sure if Lightroom copies the embedded previews to the hard drive however. In that case this won't work, and explains why the previews are so large. Embedded previews are usually full size.

You need to understand how Lightroom works, however. It shows previews, not originals, even if the originals are jpegs. That means that Lightroom will always need some preview. So maybe you should consider another application (Bridge?) for doing this kind of work if you do not want previews to be stored on your hard drive.