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Why does iphoto reduce file size of pitcures when rotated?

768 Views 7 Replies Latest reply: Jan 18, 2013 7:23 AM by LarryHN RSS
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Jan 17, 2013 5:23 PM



I'd like to import photos from the camera directly into iphoto 09 to then be able to easily delete and rotate images.  Once rotated i would like to export and save the good pitcures onto an EHD for storing and then delete them off iphoto to free space on my internal HD. (I normally keep all of my digital photos on an external hard drive in folders.... Each year has a folder, within that each month has a folder, etc. i like this method as it is organised.)


My question is: I have noticed that when a pitcure is rotated in iphoto the pitcure's file size reduces. Eg. When imported from a camera FINDER shows the file size of a jpeg pitcure to be 2.7MB. When i import it into iphoto the file size is still 2.7MB. But upon rotating the pitcure  the file size reduces significantly to 1.7MB. Even when exported as "current" image, or drag and droppped, the file size is still the reduced 1.7MB

Why does iphoto reduce file sizes upon rotation?


Pitcures rotated in Preview do the same thing. I never had this issue with PC's. Perhaps my question should be how do i easily view and rotate pitcures with no loss of quality on a MAC?


I have done web searches with the question but I can't seem to find the answer... any help is greatly appreciate!


Mac OS X (10.6.8), iphoto 09
  • LarryHN Level 9 Level 9 (54,870 points)

    where are you seeing this file size change? The only time you have a "file size" on a photo in iPhoto is when you export it and that file size is ttoally determined by your export parameters


    Exporting "current" is exporting a preview - export as JPEG using maximum quality and the file will be much larger



  • LarryHN Level 9 Level 9 (54,870 points)

    Google for an answer - Old Toad regularrly posts a link to a program that lossly rotates photos outside of iPhoto



  • Terence Devlin Level 10 Level 10 (121,695 points)

    The only way to export at the same file size as you imported is to export at the Original setting.


    Remember that the file is not the Photo. It's just a container for the photo. When you export at Original you're saying 'Put my photo into a box that has the same characteristics as the original.'


    When you export at any other setting you're creating a new file which contains your Photo. You can then decide which level of compression is applied in that file - high medium or low - and that's why the file size is different, and also why it's possible to export into a larger file than the original one. You're just putting your photo into a box that's less compressed than the one your camera created. So it has no impact on the "quality of the photo".






  • Terence Devlin Level 10 Level 10 (121,695 points)

    If you export the Original, then you get the Original. Not the Original (rotated). Just the Original. That's what you asked for.


    I would like it to have the same charactersitics ie. file size, as the original pitcure but the photo is just rotated from landscape to portrait.


    It can't have the same characteristics simple because we have no idea what level of compression your camera uses. What's important is that it is the same photo, rotated. Same dimensions, same colour space etc etc etc. That's what matters.


    Think of it this way: it allows you to virtually retake the shot, the right way round, and decide for yourself what level of compression you would like. You have more choice. You can decide to take retake the shot and save it at better quality than your camera.


    What are you using the photo for? Subsequent editing... go for lower compression levels. Uploading to the web... go for higher.


    Meanwhile, your original is alsolutely untouched. That's called lossless processing, and that's what iPhoto does.


    There are apps that do basic lossless rotation for the Mac - search on MacUpdate


    iPhoto doesn't do that. It offers richer alternatives.


    Moving from the PC to the Mac (and indeed vice versa) involves a learning curve.

  • LarryHN Level 9 Level 9 (54,870 points)

    There is nothing to sort out


    the rotated photo is not the original photo - if you export the original you get exactly that - if you export a different photo (rotated or othewise) you get a new photo with the specs you set when you export - its size is not going to be identical to the original because it is not the original


    and once again if you look there is a program that Old Toad recommends that will losslessly rotate photos prior to importing to iPhoto




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