Images restored from draft can't be posted in Safari

### Site

phanpy.social

### Version

2026.02.24.48b2cf7

### Instance

carfree.city

### Browser

Safari 18 on iOS 18.7.5

### Bug description

In mobile Safari, when a post with images is being composed when Phanpy is closed (usually as a result of a crash or paging out of memory) and reopened, the draft appears to restore successfully with the images intact, but they all fail to upload with "Validation failed: File content type is invalid, File is invalid".


This is a longstanding bug: it has never worked for me in years of using Phanpy on mobile Safari. I just hadn't gotten around to reporting it.

### To reproduce

1. Compose a post
2. Attach one or more images
3. Close Phanpy or close the Phanpy tab
4. Reopen Phanpy
5. Attempt to post the saved draft

Result: Failure to post with the above-named error showing up once for each image.

### Expected behavior

Successful post, since the images appear to be intact in the UI.

### Other

_No response_