4 Replies Latest reply: Nov 24, 2012 8:27 AM by LarryHN
Tigervision Level 1 Level 1 (10 points)

I had one large library. 41k pics. Was 150gigs.


I exported each event (dealing with corrupt library and using different time machine back ups to recover pics... That is a whole other story).


I am reimporting events into 5 different libraries.

I'm not done importing yet and I'm over 180 gigs of space for same number of pictures.


I'm comparing two same events. Before export it was 1.3 gigs. After export with same number of pics it is 2.35gigs.

I did chose during export jpeg quality of maximum. I think it defaults to medium.


Is this the reason?


What is difference between maximum and medium quality. There is also a high quality option.


Suggestions for export quality?


I assumed the jpegs from my Cannon T3i camera come at maximum quality?



  • 1. Re: Iphoto library sizes and export quality
    Terence Devlin Level 10 Level 10 (123,850 points)

    Jpeg Quality is the measure of how much Compression is used on the file.


    The settings on your camera don't matter much in this case, because it's not that file being exported.


    When you export, iPhoto puts your Photo into a new file and you can choose to set the compression level on this file. So, you have chosen to have the smallest level of compression. That's why your files are larger.


    The difference is the level of compression, as to which is more appropriate: depends on your intended use.






  • 2. Re: Iphoto library sizes and export quality
    Tigervision Level 1 Level 1 (10 points)

    Thanks TD.


    I think I read from OT that high keeps file size the same size, medium keeps half the file size. (I know that is not compression).


    If an expert like you wanted to export your photos for safe keeping (backup), would you use medium, high or maximum?  So the intended use is safe keeping and backup.


    What would you experts do?



  • 3. Re: Iphoto library sizes and export quality
    Terence Devlin Level 10 Level 10 (123,850 points)



    Thee is very little correlation between the file size on the file created by your camera and the one created by iPhoto on export. Just forget about that. It's of almost zero relevance.


    So, the fact that x or y setting produces a file about the same size as the one created by your camera means... nothing. It's a different file, created with different settings, and  - if you have edited the shot, added metadata or whatever - it has different contents.


    So, the question is... what am I going to do with this file? Upload it to a website keep the file small. Archive for posterity? I would use the largest file size - leaves you most to work with.

  • 4. Re: Iphoto library sizes and export quality
    LarryHN Level 9 Level 9 (56,675 points)

    Personally I do not backup photos - I backup my iPhoto library - with Time Machine hourly and daily with Carbon Copy Cloner plus an occasional off site backup - that gives me full flexibility on what to do and quality since I have everything


    If I were going to bakcup just part of the information, the photos, I would use the maximum quality