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Fuga

macrumors member
Original poster
Sep 11, 2011
56
15
I routinely have need to convert PNGs from 600 PPI to 300 PPI. Individually I can open an image then choose Picture>Size>Scale in which I can choose to keep the same width/hight but change the PPI. Great, exactly what I want and do. But I would like to make use of GC's batch abilities. I can not find the right processes/settings/whatever.

If I choose 'Resolution' I then can choose to set the PPI and also to 'Convert picture' or not. If I do choose to convert the picture I get the decreased resolution but also decreased hight/width. Not what I want. If I choose not to convert the picture hight and width are maintained but the files grow (e.g. from 11 MB to 13 MB). I get the same width hight and decreased resolution but at a larger size. Again, not what I want.

I tried adding another process: Scale, with hight/width to stay 100%. I then set the resolution to 300 and choose to convert the picture and had it higher than the Scale process, hoping it would run, reducing the resolution and then the Scale would insure the hight/width would be the same.

Nope. Gotta believe I'm doing something wrong and/or neglecting something!
 
Meh. Found my way to EasyBatchPhoto. But Reformator X is but $10 USD.
 
Meh. Found my way to EasyBatchPhoto. But Reformator X is but $10 USD.
Preview that came on your computer will do this. You can do a lot of Batch editing with it, but you have to drag and drop all the images to it (you can drop a folder on it as well), not just one at a time. When they are all in Preview you will see them in the side bar. Select the ones you want to change or use "command A" to select them all at one time. Then go to the Tools menu and select "Adjust Size".
 
Preview that came on your computer will do this. You can do a lot of Batch editing with it, but you have to drag and drop all the images to it (you can drop a folder on it as well), not just one at a time. When they are all in Preview you will see them in the side bar. Select the ones you want to change or use "command A" to select them all at one time. Then go to the Tools menu and select "Adjust Size".
Works perfectly. Thanks!
 
It's may also be worth having a look at Automator (see your Apps folder) if you find yourself doing a lot of "batch" processing. There are quite a few easy-to-use Preview actions that you might find useful. You can use them to make a droplet, hot folder etc.

If you feel brave and maybe want to go one step beyond the drag and drop stuff, I wrote a quick guide to SIPS and Automator here: https://www.ghostotter.com/batch-image-processing-mac-os-x/
 
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