# Question about .lrprev files in Lightroom



## ZimPhoto (Feb 8, 2013)

It appears that every edit I make in Lightroom 4 creates and individual preview file.  These individual files are storing themselves in my picture library.  Editing a single picture may leave 200+ files that range in size from 9 KB to 600+KB.  This could take up 20GB + inside of my picture gallery.  Hundreds of files are sandwiched in between my pictures.  Below attachment is what MyPictures folder looks like.  What am I doing wrong or what settings do I need to change?   I am using a PC and running Window 7 Home Premium 64-Bit.  If I've left anything out that would help answer my question please let me know. Thanks!


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## KmH (Feb 9, 2013)

Lightroom is a parametric image editor that cannot edit pixels.

A Lightroom 'edit' is a XML line command that affects one of the algorithms in the rendering engine. As each 'edit' is made it is essentially a software generated preview added to the original image file.

All those .lrprev files are used to display photos in the Library module and filmstrip and should be packaged in Lightroom Previews .lrdata files.
The size of the thumbnail cache depends on the Catalog Settings - File Handling preferences you have chosen.

To keep the Lightroom Previews .lrdata size to a minimum set Automatically Discard 1:1 Previews and choose the after 1 day or 1 week options.
Since hard drive space is now so cheap, many Lightroom users have that set to 30 days or Never. Otherwise Lightroom will always be re-generating the previews in the background while you're doing work in the foreground.

If you don't already have it, I highly recommend my source of the above information, the Lightroom 4 training and reference book - Adobe Photoshop Lightroom 4 Book: The Complete Guide for Photographers


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## ZimPhoto (Feb 10, 2013)

Thanks!  I've updated that setting.  The file path looks like it is under a folder labeled 'Backup' and the .lrprev files I'm seeing are in the actual folders where my pictures are filed.  Hopefully the updated retention setting will help this.  I'll also check out the book you recommend.  Probably won't be the last question I have!


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