Why is picture size reduced automatically during import?

Question

Level 1

8 points

Why is picture size reduced automatically during import?

Hi all,

today I noticed the following problem during import of pictues (JPEG´s) on my Mac:

By importing pictures of my DSLR with 'Photos' and exporting afterwards (irrelevant wether copy&paste or export-function!) the exported files are much smaller than the original one´s. I´m not talking about picture size (pixels) but file size. Example: original -> 4.2MB, after import -> 1.6MB.

I noticed that this resizing is made during import because also the saved pictures on filesystem ('mediathek') are smaller. I saw that DPI value has changed.

I want prevent to save my photos with less quality as the original one´s and cannot imagine that no data get lost during this resizing.

- Does anybody know this behaviour?

- Is it possible to edit the import configuration?

- Is there any possibility to get the original data?

Thanks in advance!

Regards

Sebastian

MacBook Pro, macOS Sierra (10.12.1), Early 2011

Posted on Nov 29, 2016 11:45 AM

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Answer 1

Old Toad

Level 10

215,718 points

Nov 29, 2016 12:07 PM in response to Snoozleberg

It depends on how you're exporting the photos out of Photos. If you use the File ➙ Export ➙ Export unmodified original for XXX photos... you will get the exact same size as what was imported.

However if you've edited the photos and export using the File ➙ Export ➙ Export XXX photos... you will get a variety of file sized depending on the JPEG quality level you choose.

I've found the High setting gives me close to the same file size as the original. Maximum produces a larger file size (don't ask me why).

Unless you're going to print extremely large prints you should be hard pressed to see any image degradation from the High setting.

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Answer 2

Old Toad

Level 10

215,718 points

Nov 29, 2016 12:20 PM in response to Snoozleberg

Photos does a bit by bit copy of the image file into the library. There is not reduction of file size for the original/master file in the library.

Run this test:

1 - Download some photos from your camera to a folder on the Desktop.

2 - Check their size.

3 - Import into your Photos library and then export at several different settings and check the sizes.

This should help up see where the reduction is taking place.

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Answer 3

Old Toad

Level 10

215,718 points

Nov 29, 2016 3:10 PM in response to Snoozleberg

- Export to Desktop per Drag&Drop: 5.8MB

This should have given you a smaller file unless you held down the Option key during the drag which will give you the original file.

Is there any difference by importing manually or automatic import when SD card is accepted?

No. Regardless of how it's imported it's a bit by bit copy.

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Answer 4

Snoozleberg Author

Level 1

8 points

Nov 29, 2016 12:16 PM in response to Old Toad

Hi,

thanks for your reply! I tested your solution:

1. When I use 'Export unmodified original' I get the small size again (1.6MB) and not the original size of 4.2MB which I can see on SD card from DSLR.

2. When I use the 'normal' export function and set quality to 'maximum' I get nearly the same size as the original...

How is this possible?

Regards Sebastian

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Answer 5

Snoozleberg Author

Level 1

8 points

Nov 29, 2016 12:40 PM in response to Old Toad

Hi Old Toad,

now I´m totally confused :-D

I made your written test:

- Add photo to Desktop: 5.8MB

- import into 'Photos': 5.8MB

- Export as Original: 5.8MB

- Export to Desktop per Drag&Drop: 5.8MB

?!?!

But I have 100% other pictures in my album folders which are smaller as on SD Card (unfortuantely I´ve already deleted them on SD card and cannot retest it)....

Las idea: Is there any difference by importing manually or automatic import when SD card is accepted?

Regards Sebastian

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