May I ask why you are so concerned with the file size? To most people dealing with image editing that is there last concern.
I personally don't care what the file size is. For the cameras I own the file sizes are basically always the same. Only varying be a few thousand bytes. My Fuji X-E2 raw files are always around 32MB. The Panasonic LX100 raw files are around 14MB.
About the only time I am concerned with file size is if I am sending images to someone in an email or uploading to a website.
I agree that file size should not be a concern, and isn't even determined until you export the photo anyway for some file types ... Megapixels or Crop Dimensions is what you should be using.
Anyway, there is no such option to show file size in Lightroom. Use Megapixels or Crop Dimensions, its a much better number.
Sure. I have a catalog with 22,000 images indiscriminately imported from hundreds of folders and multiple drives from this year alone (partially lost a RAID array to a corrupt index and recovered a dump of the files so I'm terribly disorganized juggling emergency redundancy backups wherever I had 50 gigs here, 100 gigs there, and working to clean up and organize my photos one year at a time ), including raw, jpg, websized jpg, png, tiff and psd (flattened and with layers/adjustments) and am now trying to identify my keepers and delete unnecessary files. I have 22 terabytes of personal files and photography spread chaotically and while I now have proper discipline when saving variants, I didn't always and want to remove unneeded, rejected, and duplicate images. I don't expect to be caught up for months or longer depending on my free time and sanity. Unfortunately, it's not as simple as keep the raw delete the rest. Sometimes I have multiple PSD documents with different version names and edits, sometimes with multiple layers, and I have to use a variety of information to identify which one is indeed the correct one to keep...or open them all/both.
Often, file size can be an indicator for me and aids in making the decision more quickly. For instance between 2 psd files with the same Megapixles I'm often able to identify the flattened version vs the layers intact version by file size if it wasn't properly noted in the filename, which unfortunately due to a combination of bad or evolving practices and being tired or rushed happens more often than I'd like to admit. One I just came across that brought me here searching was 3 similarly named and appearing PSD files of a panorama, all with the same MP/dimensions. One was flattened, one was the original stitch, and one was flattened with a few masks, adjustments, and an extra layer, and being the one I'd want to keep. Filesize helped me quickly identify which was which. Also sometimes dimensions are misleading, like when a panorama is first created and uncropped, its dimensions are larger, but a tighter cropped image with multiple layers and a larger file size indicates to me that it is newer and more finished, even though smaller dimensions typically indicates a crop and may not be a 'master' copy. Additionally, 2 images with different names but the exact same file size are very likely duplicates (at least in my workflow) but 2 similarly looking images with the same dimensions could be retouched/not, sharpened/not, have noise reduction/not, and I'd have to view them in detail to determine if they were in fact identical. For my purposes (since these are my personal fine art images & I have the raw files incase I occasionally mess up) I'm often willing to trade an educated guess for my time. Seeing identical file sizes on 2 apparently similar images is good enough for me to delete one.
I can select them individually and check...it's not a horrific problem. But it would save me time so I was hoping I had simply missed how to view that. My reasoning is 'why not' have the option available with all the others? Me personally, I don't care about megapixels when I already have the dimensions, that's just redundant and honestly much less helpful than LxW. File size would be an additional tool I would use, though. There are other examples but the main thing is that I do spend time checking filesize, and specifically when comparing multiple images, so having it displayed in the cell would be a time saver for me.
I understand what you're saying, and I agree that dimensions are very useful. However, I can positively attest that file size helps me with the task at hand and would have been helpful if available. I believe you that it isn't, which is unfortunate, but I had already assumed as much and came here for verification. The first response asking why was fine, as I know my problem is unique, and I think I gave a more than adequate reply. Telling someone what they don't need without knowing why they ~think~ they need it, simply because you don't, doesn't contribute much to the conversation, but thanks for your opinion.
Good explanation of why the file size is helpful in your case.
Unfortunately, LR does not show that to you.
Then use a File manager program like Finder or Win Explorer. You can ever sort by the file size.
If at some time you renamed images during importing to LR or even when copying them from a card to your hard drive then the file size sort can be confusing. I always leave the files with the original name and then if I edit it I add Edit if I make it B&W I add that as well. But the first part of all my image file names is what got assigned by the camera. To me that make is simpler to look for duplicate files.