batch compress or downscale images

Question

batch compress or downscale images

Hello,
My mother has a 10 megapixel camera. At top quality, it uses about 4MB per picture, though 90% of her pictures she doesn't want to blow up to A2 size (or crop smaller). I'd like to be able to do a batch downgrade of pictures to 5MP, perhaps with greater compression.

Is there any way of doing that?

MBP 2.2, Mac OS X (10.5.1), I have a few....

Posted on Dec 28, 2007 4:26 AM

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Answer 1

Yer_Man

Level 10

165,954 points

Dec 28, 2007 7:20 AM in response to Greg Alexander1

Select the pics in the iPhoto Window and use the File -> Export command. In the resulting dialogue you have the option to resize and compress the pics - among other things. Then complete the export to the desktop.

Now you have your compressed pictures.

Trash the others in iPhoto (Move to the iPhoto Trash then empty the trash.) Now that's the full scale pics gone.

Re-import the compressed pics back into iPhoto.

The downsides? Aprat from the fact that you've just halved (or more) the quality of the pics, you've alos utterly defeated the Lossless editing feature of iPhoto.

IF disc space is an issue, you know you can run iPhoto from an external disk:

1. Quit iPhoto

2. Copy the iPhoto Library Folder as an entity from your Pictures Folder to the External Disk.

3. Hold down the option (or alt) key while launching iPhoto. From the resulting menu select 'Choose Library' and navigate to the new location. From that point on this will be the default location of your library.

4. Test the library and when you're sure all is well, trash the one on your internal HD to free up space.

Regards

TD

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Answer 2

Old Toad

Level 10

215,652 points

Dec 28, 2007 2:13 PM in response to Greg Alexander1

Greg:

For future pictures from her camera check the size and quality settings. I'm sure there's a setting to either reduce the pixel dimension (this limits printing) and to change the compressions level (which will still let her print but reduces the file size.

Another option to to batch change the files before importing with Resize!. With it you can set the maximum pixel dimension you want for the photos and select a quality/compressions level. I've reduced 2718 x 2112 file at 3 MB down 1.1 MB with a Quality level of 60% and keeping the pixel dimensions the same. Just remember that once you downsize there's no going back.

Happy New Year

TIP: For insurance against the iPhoto database corruption that many users have experienced I recommend making a backup copy of the Library6.iPhoto database file and keep it current. If problems crop up where iPhoto suddenly can't see any photos or thinks there are no photos in the library, replacing the working Library6.iPhoto file with the backup will often get the library back. By keeping it current I mean backup after each import and/or any serious editing or work on books, slideshows, calendars, cards, etc. That insures that if a problem pops up and you do need to replace the database file, you'll retain all those efforts. It doesn't take long to make the backup and it's good insurance.
I've created an Automator workflow application (requires Tiger), iPhoto dB File Backup, that will copy the selected Library6.iPhoto file from your iPhoto Library folder to the Pictures folder, replacing any previous version of it. It's compatible with iPhoto 08 libraries and Leopard. iPhoto does not have to be closed to run the application, just idle. You can download it at Toad's Cellar. Be sure to read the Read Me pdf file.

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Answer 3

Dec 28, 2007 11:23 PM in response to Yer_Man

I will look further into an external library, and various ways of down rezing outside of iPhoto - I was hoping some app could reduce the resolution within iPhoto. Oh well.

My mother really wants the best of all worlds and won't take no for an answer... though she may have to.

She has a very nice new camera, and in the past has occasionally blown up her shots to A2 size or larger - but for most she needs A5 size at best. She wants the quality taken on her camera and then downgrade after. And, unfortunately, she's on a laptop and she wants access to her photo library from several locations (including when she's got no internet connection).

Ideally, she'd use an external huge photo library, and "sync" a subset to her laptop, in a similar manner to syncing subsets to the iPod or iPhone (ie: only some libraries, and a smaller resolution). Pity Apple doesn't offer that, though I have hopes for this in future (ie a media centre or similar, with laptops syncing a subset of data).

Thanks both.

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