A very common use case in our iOS app is that users take a large number of pictures (about 30) in low-light conditions using the camera app, and immediately after, they try to upload them to our servers.
We measured the time to load photos from the PHPickerResult. For most photos, it takes less than 100 milliseconds, but for some of them, it takes several seconds—we even saw minutes in some extreme cases.
We believe this started happening with iOS 17, when deferred photo processing was introduced. If users take the pictures using our in-app camera experience, the options to customize the camera are enough to avoid the long waiting times. However, the majority of our users still prefer to take the photos with the camera app, and there is little we can do about that.
In the past few weeks, we tried many combinations:
Without asking for permissions, we tried loadFileRepresentation, loadData, and loadObject.
We explored the PHImageManager route, asking permissions and with different options for deliveryMode, resizeMode, version, isSynchronous, and allowSecondaryDegradedImage.
We also tried fetching the photos in parallel, with very bad results.
In summary, nothing helped the long waiting times—minutes in some cases.
The first question is then, is there anything we can do to ignore the post-processing of the photos and get them fast? We could accept the unprocessed images.
At a minimum, we would like to show our users what we are doing and why we are taking so much time. We tried to load thumbnails with loadPreviewImage and put a progress indicator on top. This method consistently gives us an error for all photos:
(lldb) p error.localizedDescription
(String) "Cannot load preview."
We can load thumbnails with the PHImageManager option, but it seems excessive to need to get permissions only for that.
Second question would be then, what can we do to load thumbnails without asking for permission?
I created a feedback report with a video and sample code to reproduce -> FB15493683
