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The Case of the Missing Thumbnails
It’s frustrating getting simple questions I can’t answer. The other night, at the Apple store in San Francisco, I talked about the Adobe Photoshop Lightroom Adventure, and then demonstrated Lightroom. When I was finished with my song and dance a hand immediately shot up and asked: “Why doesn’t Lightroom generate thumbnails on export that can be seen on my Mac desktop?” I was stumped. In fact, I never noticed that Lightroom didn’t generate a thumbnail and I also work on a Mac.
I did what I usually do when I don’t have an answer. I told the questioner he must be wrong. No, not really. But I did turn to Lightroom and tried to get on solid ground by explaining things I know. I opened the export dialog box and showed how you can make web-friendly JPEGs by checking the Minimize Embedded Metadata box. This creates an image with as small file size as possible, much like Photoshop’s Save for Web plugin. And of course, in order to keep the file size down, a preview thumbnail would not be generated.

“Ah
maybe you accidentally checked this,” I said. “That might explain your, er, problem.”
“No,” replied the questioner, quite sure of himself.
Anyway, to cut to the point, the questioner was right. As you can see, Lightroom, unlike Photoshop, doesn’t create a thumbnail preview for the Mac. (I’m not sure what is gong on with Windows, but this doesn’t seem to be a problem on that platform.)
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Ok, Googling the words” thumbnails Lightroom” turned up some chatter on the subject, but no answers.
So I turned to God, no I mean Adobe’s Mark Hamburg, the man who dreamed up Lightroom. This is what he wrote back:
“Our export logic is platform agnostic and hence doesn't generate Mac
specific thumbnails.”
“And by the way,” he added, “Camera Raw doesn’t generate thumbnails either.”
Ah got it. Case solved? Back to answering the really hard questions.
PS. A big thanks to everyone who wrote in with errata from my Lightroom book. Almost all the corrections were made and the 2nd printing is now at the printer. You’ll get your free copies as promised in a few weeks.
Comments (8)


Yes, sad but very true. I don't understand how something as that simple and fundamental can go unnoticed on Adobe's side.
Actually if it was only export, but people who like to have metadata written straight to the file (instead of a sidecar file) their thumbnails disappear every time metadata is modified (like add or remove keyword etc.).
I am sure Adobe could fix this easily, but I am starting to wonder whether they consider it a bug.... :-( I know I do.
Cheers
Marek
Actually I managed not to expand and read your whole article. After I posted, I did, I found out indeed that Adobe doesn't consider it a bug and are not really bothered by it (the reply looks like that or is it just me?).
Could you do us a favor and ask again why Windows have no trouble to show a thumbnail? By the reply given to you it would indicate that XP (in my case) generates the thumbnail on the fly if not embedded in the file?
I will emphasize here that I am not talking about export function but rather keywords writing into JPEG which makes the thumbnail sadly disappear (Mac only, not in Windows as discribed above).
Thanks
Marek
“Our export logic is platform agnostic and hence doesn’t generate Mac specific thumbnails.”
This is an engineering answer, not a good product answer. As a user, I don't particularly care why it doesn't work. It doesn't work.
I'd be more impressed if Adobe put the effort in to provide previews specifically for the Mac platform. After all, it is where they have the most competition for Lightroom with Aperture.
I found this really frustrating after coming from Lightroom on Windows. Adobe's stance is correct, the application simply generates the jpegs, it's not responsible for showing you previews in your OS.
The simple OS X solution was enabling Show Icon Preview in the Finder folder options. Annoying that it isn't a default setting in Finder, but it does solve the problem.
I agree with Geoff Wilson's comment that Adobe is giving us an engineering answer, not a good-product answer. That said, Mac users who want icons may like Pixture's free QuickImage contextual menu plug-in. Right-click (Control-click...sigh) on a group of generic photo icons and QuickImage will offer to create thumbnails. It has several other handy features as well. I use it daily.
David,
the only problem is that it's painfully slow and you have to technically doing every time you either export or touch XMP data in my case.
I think the summary has been well versed by saying that the from Adobe gave an engineering answer which us a customers of Adobe's product don't care for. If PhotoMechanic and I am sure many others do it right, why not Adobe?? Or is Adobe saying that every deficiency in Windows is not being addressed in LR so it does what Mac version does. I think it works both ways, they just dropped the ball here, period.
Regards
Marek
Mikkel,
One can force thumbnails when exporting out of Lightroom but you have to set up Finder - go to View -> Show View Options and then check the box "Show icon preview" and make sure you check "All Windows" if you want this behavior in all folders. This needs to be repeated for the desktop if you save to the desktop. (Only need to do this once) If you save to an open folder, it needs to be refreshed (closed and opened or just single click on the file). Also you need to single click on the file if saved to the desktop even if you set "Set icon preview". Hope this helps. MacPro OSX 10.4.10
I don't see this as a Mac-only issue. EXIF data in Jpegs support saving thumbnails internally in the file, and these thumbnails are in turn used by many digital cameras and printers (Like the Canon Selphy CP720) to show your pictures. Because Lightroom takes out this information when exporting, I subsequently have no idea what image I am printing on this device!