When you delete a smart preview (which you can't see directly), the library previews (which you can see) remain.
PS - Smart preview files are cleaned up upon Lr startup, if more than one hour has elapsed since their removal.
Also: remember to empty recycle bin before assessing hard drive space reclamation.
Smart previews are small DNG files that let you work on your photos when the actual full size files are not present on any hard drive connected to your computer. What you see in the library module are "normal" previews, i.e. jpeg files, that are not deleted, unless you remove the photos from the catalog. So, what you are experiencing is just the normal behaviour of LR. As for the space disk not increasing when you delete the smart previews, as it should, may I ask if you are emptying the trash/recycle after?
Thank you for the response. I'm not sure what a "library preview" is. I have my LR library on an external drive. I have smart previews on my laptop. When I disconnect my external drive, I still see the images of the files that I have deleted the smart previews for. When I select the image and look at the histogram, there is no information in the histogram and underneath it, it says "photo is missing". If the photo is missing, then why am I still seeing it?
When I go into the Devolp module, I get a message that says "The file could not be found". I agree that the file should not be found because I deleted the smart preview and the external drive is disconnected. So why am I still seeing the image? If I'm seeing it then I imagine that it must be taking up space on my hard drive. I have several thousand smart previews that I would like to delete so hard drive space is a concern. I have also emptied the recycle bin. Thank you again for any help.
Thank you for the response. The "normal" previews that you are talking about I believe should only be visible when my external drive that contains all of my LR photos is connected. Why am I still seeing these previews when my external drive is not connected and, as far as I can tell, my smart previews have been deleted? The recycle bin has been emptied. There is nothing in the trash. Thanks again for your help.
I'm not sure what a "library preview" is.
It's what you see in Lightroom, when you are looking at a thumbnail or loupe view (typically in library module, but used for slideshows and other stuff too).
The smart previews should "probably" (arguably) not be called previews, since, well, you can't really view them directly - they are more like mini-versions of your original photo source files.
The point being, when you remove a smart preview, it doesn't (shouldn't, won't..) change what you see in Lightroom. Just like if you (don't have smart previews and) delete the original photo source file from your hard drive (outside Lr, e.g. in explorer/finder) - you won't be able to edit anymore or export.., but it doesn't change what you see in Lr library (other than the missing photo indicator I mean).
The idea of smart previews is so you can edit when that external drive (or network connection) is not available. The idea of library previews is so you always have something to see, whether original or smart preview is available or not.
PS - Library previews are created by rendering your original photo source files *or* smart previews (if original unavailable).
PPS - You can remove the biggest library preview (1:1, for zooming) by using Library -> Previews menu, but the "only" (normal) way to get rid of the smaller versions is to remove the photo from your catalog. In other words, Lr wants you to always have some kind of image to represent your photos in grid and loupe (even if not zoomable) - those images are the library previews.
Thank you for your help Rob. I completely understand what smart previews are and how they are used. My question is this:
If my LR library is on an external drive and that drive is not hooked up to my computer and there are no smart previews associated with a particular image, should I still be seeing the image in the Library module? I though the answer would be no but maybe I am wrong. Thank you.
You're welcome EditMike.
If my LR library is on an external drive and that drive is not hooked up to my computer and there are no smart previews associated with a particular image, should I still be seeing the image in the Library module?
You will always see all images in your library no matter what, via standard library previews (as long as said previews exist I mean, and since there is virtually no way to get rid of them, once they've been built, they will exist forever, until photo removed from catalog).
If your concern is for hard drive space (on drive with catalog), then you can remove all smart previews and all 1:1 library previews. That's the best you can do (short of more drastic measures I mean..).
If you have another drive with more space, you can either move the catalog folder there, or just move the previews there then set a link to them, if you know how..
Thank you so much Rob. This makes perfect sense now. So if I delete smart previews and 1:1 previews and disconnect my external drive that contains all my photos, I will still see the photo via standard library preview when I open LR on my laptop Thank you for clearing that up for me. I appreciate your time.