Preserving original media timestamps when saving to iOS Photos app

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• I am submitting a bug report for existing functionality that does not work as intended
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Bug description

When saving images or videos from Signal to the iOS Photos app (either individually or via bulk export from the Media Overview), the original sent/received timestamp is lost. Instead, the "Date Created" in the iOS gallery is set to the moment of the export (the "now" date).
This makes it very difficult to organize media, as photos from months ago appear as the most recent items in the system gallery, breaking the chronological order.

Steps to reproduce

• Open a conversation in Signal.
• Tap on the contact name to go to the "Media, Files & Links" overview.
• Select one or multiple older images (e.g., from several months ago).
• Tap the "Share" icon and select "Save [X] Images" to export them to the iOS Photos app.
• Open the iOS Photos app and check the "Library" (All Photos) or the image details/metadata.

Actual result:
The exported images appear as the most recent items in the iOS library. The metadata shows the "Date Taken" or "Date Created" as the current time of the export, instead of the original timestamp when the media was sent/received.

Expected result: The images should be saved with their original timestamps (or the message timestamp) so that they are correctly sorted chronologically in the iOS Photos app.

Device info

Device: iPhone 15 Pro
iOS version: 26.2
Signal version: 7.89 (1253)

Start at the Media, Files & Links overview and the Share action that performs “Save [X] Images,” then trace how exported images and videos are written to the iOS Photos app. Reproduce with older media and inspect the saved metadata; done means the original sent/received or message timestamp is preserved and the media remains chronologically ordered.