FolderSize is a free Lightroom plug-in that loops through all the selected images and analyses them by folder. It counts them and shows how much disc space they use.
For a long time I’ve stored image files on my hard drive in daily subfolders, which are themselves inside DVD-sized folders – “buckets” in Kroghspeak.
The idea is that these buckets are then backed up to corresponding DVDs, sequentially-numbered, so one can easily reconstruct the folder system after a crash and without depending on any proprietary backup software. In this system, you often need to check if you’ve accumulated enough files to burn a DVD and start another bucket. The problem is, Lightroom doesn’t show how many megabytes you’re wrestling with, and you have to flip over to Explorer/Finder. That’s not the only reason why I sometimes want to know the size of a group of files, but it’s frequent enough to irritate me (thought it doesn’t take much). So a couple of years ago I wrote a little Lua plug-in FolderSize (zip file) to help do the job.
You just select some images in Grid, choose Library > Plug In Extras > Size and count, and this little dialog box appears. As the selection changes, the folder analysis updates automatically – you don’t have to keep opening and closing the dialog box (it works best on a second screen).
If you untick Folders View it then calculates the size of the selected images. I use this mode for building psd/tif buckets.
The plug-in is free, but you can always say thanks via Amazon.