Why does Image Capture import fewer pictures than it counted? I recently used Image Capture to get a backup of my iOS Camera Roll, and noticed a discrepancy.

In the footer of the app, Image Capture notes the number of items on the device, or the number selected if they are individually selected. But after Import All (or select all then Import), the number of items in the folder on my Mac was a smaller number.

Image Capture is version 6.3 (502.1)
OS X 10.9.5 Mavericks

iTunes - running or not running, same results.
Preview not running.
No other camera-acquisition apps.

Replicated this behaviour on 2 iOS devices:


iPhone 6 / iOS 11.4.1 (15G77) with settings:


iCloud Photo Library is OFF.
Optimize iPhone Storage is disabled.
My Photo Stream is OFF.
iCloud Photo Sharing is OFF.
Cellular Data (for Photos) is OFF.
Transfer to Mac or PC is Automatic (not Keep Originals).

iPad 3 / iOS 9.5.3 (13G36) with settings:


My Photo Stream is OFF.
iCloud Photo Sharing is OFF.
Optimize iPhone Storage is not available.



USB cables are original Apple, for both devices.

Videos import fine.
Edited photos import fine.
Hidden photos import fine.

Photos with the same filename, but different dates, also import fine. One of the devices has more than 10,000 photos, and since the filenames are IMG_0000 to IMG_9999 (with JPG, PNG, MOV, etc. extensions of course), there are only 10,000 unique names. I have, for example, an IMG_3955.JPG from this past March, and another IMG_3955.JPG from July 2014. The older one imports as "IMG_3955 1.JPG"
Duplicated photos seem to be the culprit. That is, photos added to the Camera Roll by means of the iOS Photos app's "Duplicate" command.

Photos are stored in the Camera Roll ordered by the time they are created. So if, on August 23, you Duplicate a photo from August 11, it will show up as the last picture on your Camera Roll... but you might notice scrolling through Camera Roll photos in order, that this Duplicate shows up with the August 11 date, same date as the original.

I have 3 photos (visible as separate items both on the device and in Image Capture) with name IMG_9234.JPG and the exact same date/time. Only one copy was imported.

Apparently when Image Capture sees these a photo with the same exact filename and same timestamp (which is probably a last-modified time, rather than a created time), it either ignores the picture (thinking it was already imported) or else it overwrites the last one it imported.

I'm not sure if this is a bug, an oversight, or was intentional.

But the discrepancy in the count is very annoying, since the number can't be used as a quick confirmation that all the photos were correctly imported.