How can I use Apple Photos to crop an image to a specific size?
I need to produce an image that is 10" on each side, with 3000 pixels across each side.
Question marked as
Do you need an image file for uploading or a print out?
After cropping a photo to square (in Edit mode) we can export an image file with the required width and height in pixel:
- File > Export > Export ... image.
- Set the "Size" to custom and set the width to 3000.
This will give you a file with the correct resolution, but only, if the image still has 3000 pixel at the longest edge. Photos will not fill in more pixels, if the image resolution is poor. You would need a tool like the online image enlarger to fill in pixels without making it blurry (Online Image Enlarger).
What Photos not supports is to set a custom dpi tag on export to state that the image has to be printed with 273 dpi to give it a width of 11" when printed. We can print the exported image file at any size; the app we are using to print the photo should take care of the print size. If you need an image file for uploading with a dpi tag to control the print size, you would need to set this tag with exiftool or an editor that can set this tag, for example: Quick Action: How to change the dpi tags … - Apple Community (I wrote this tip for Mojave, you may need to adapt it to your current system version).
Yer_Man already pointed out, that we can print photos directly from Photos. To get an image file with a width of 11", you could save the print to PDF.
