Image Sent from App 4x LARGER than Camera Roll

[DenVog]

I have an app that combines a graphic with a photo from the built-in camera to create a single composite image. I'm using UIImageJPEGRepresentation and setting the dimensions to 600 x 800 for the final image. After saving the image to the camera roll, users have the option of using MailComposer to send it somewhere.

The image saved to the Photos App Camera Roll is:
591 x 800, 106 KB jpg.

Using MailComposer to email the image from within the app:
600 x 800, 438 KB jpg.

It should be the same image! Why is the photo in the camera roll 591 instead of 600? Why is the photo sent from the MailComposer 4x as large?!

I'd really appreciate if someone can shed light on this. I've tried a couple different implementations and get the same result.

[DenVog]

Does anyone know what compression level UIImageWriteToSavedPhotosAlbum uses for a JPEG saved to the camera roll? I've looked in the docs and forums, but can not find it listed. I assumed it was 1.0, but if it's not it would explain the difference in file size (KB).

Still don't understand the dimension 591 vs. 600 difference.

[DenVog]

Originally Posted by DenVog

Does anyone know what compression level UIImageWriteToSavedPhotosAlbum uses for a JPEG saved to the camera roll?

I've not been able to find an official answer to this, but through trial and error my file sizes end up very close to the same if I use .7 for the UIImageJPEGRepresentation compressionQuality setting.

I've exhausted my troubleshooting to understand why the camera roll photo saves at 591x800 instead of 600x800. Any suggestions would be very much appreciated.