LIGHTROOM: File size differences

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  • Updated 4 years ago
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I am going through my catalog of photos to weed out the large Tiff files that I don’t need anymore. In doing this I noticed that I see on my Mac Mini with Lightroom 4.4 that I see three different file sizes for the same picture. In the INFO panel, in loupe view and library grid. Then even ‘Finder’ shows a different size. I want to go through photos and delete ones that are too large since I might have 4 versions of the same photo, just in different sizes. Its hard to tell what the actual file size is. I want to trust ‘Finder’ but i’m not sure. I read somewhere that it might show something about the size before editing, but that is just plain confusing and she actually state that specifically instead of just being implied. I could not find anything about this on a forum and hardly anything in the last couple years.
Thanks,
Scott
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Scott Ludgin

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Posted 4 years ago

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Jim Wilde, Champion

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Trying to ease one of your concerns, the 17.9 figure is actually "megapixels" (MP), not "megabytes" (MB)....one is the total number of pixels in the image, the other is how much space that the file occupies on disk. I would imagine that the 17.9MP figure is what you also see in the Loupe view, I'm pretty sure the file size (MB) is not a View Option.

But I have no idea why Lightroom and Finder are reporting different MB values, that's not something I've seen on the Windows platform (though I don't check very often).
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Scott Ludgin

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Jim,
I understand about the MP and MB. That makes sense to be a little bit off, such as 1.1 megabytes difference. The main problem is that Finder on a Mac Mini is drastically different. Any suggestions on who to contact about this? I can call/go to an Apple store but I am almost certain they will tell me to contact you. I’ll try regardless.
Thank you for your quick response, much appreciated.
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Jim Wilde, Champion

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I've just had a further look at what Windows displays, and played with my calculator, and I suspect that the Finder display of 24.6 MB is not actually reporting 24.6 megabytes, but rather 24.6 million bytes....and there's a difference. 24.6 million bytes is actually 23.46 megabytes. Certainly would explain the different totals. Is there a display that shows the actual number of bytes of the file? If so, divide that by 1024, then again by 1024, and that will give you the number of megabytes as displayed by Lightroom.

It can be confusing as there are different values displayed in different places. On Windows I can get a display of actual bytes, a value for kilobytes, and another for megabytes. But they tend to look different because the multiplier/divider is 1024, not 1000.

Hope that makes sense....