IImage Downsize() throws an Exception in 9.0.81 when called from a background thread on iOS.

[brentpbc]

Description

IImage Downsize() throws an exception in Maui 9.0.81 when called from a background thread on iOS. Note this works in 9.0.71. Also in 9.0.81 the orientation and file size appear to be wrong compared to 9.0.71.

9.0.71

iOS_Maui_9.0.71_video.mp4

9.0.81

iOS_Maui_9.0.81_crash_video_a.mp4

Steps to Reproduce

Sample app demonstrating issue:
https://github.com/brentpbc/maui-camera-settings/tree/main

Use branches to switch between 9.0.81 and 9.0.71 maui versions.

1. Select an image using camera or photo picker
2. Adjust size/compression sliders to have image reprocessed on a background thread, this will throw an exception on Maui 9.0.81, also file size and orientation appear to be wrong.

See readme for more info.

Link to public reproduction project repository

https://github.com/brentpbc/maui-camera-settings/tree/main

Version with bug

9.0.81 SR8.1

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

9.0.70 SR7

Affected platforms

iOS

Affected platform versions

iOS

Did you find any workaround?

Revert to Maui 9.0.71 or wrap call to IImage.Downsize() in MainThread.InvokeOnMainThreadAsync().

Relevant log output

UIKit.UIKitThreadAccessException: UIKit Consistency error: you are calling a UIKit method that can only be invoked from the UI thread.
   at UIKit.UIApplication.EnsureUIThread() in /Users/builder/azdo/_work/1/s/macios/src/UIKit/UIApplication.cs:line 137
   at UIKit.UIGraphicsRendererContext.get_CGContext() in /Users/builder/azdo/_work/1/s/macios/src/build/dotnet/ios/generated-sources/UIKit/UIGraphicsRendererContext.g.cs:line 202
   at Microsoft.Maui.Graphics.Platform.UIImageExtensions.<>c__DisplayClass1_0.<ScaleImage>b__0(UIGraphicsImageRendererContext imageContext)
   at ObjCRuntime.Trampolines.SDActionArity1V263.Invoke(IntPtr block, NativeHandle obj) in /Users/builder/azdo/_work/1/s/macios/src/build/dotnet/ios/generated-sources/ObjCRuntime/Trampolines.g.cs:line 35814
   at UIKit.UIGraphicsImageRenderer.CreateImage(Action`1 actions) in /Users/builder/azdo/_work/1/s/macios/src/build/dotnet/ios/generated-sources/UIKit/UIGraphicsImageRenderer.g.cs:line 196
   at Microsoft.Maui.Graphics.Platform.UIImageExtensions.ScaleImage(UIImage target, CGSize size, Boolean disposeOriginal)
   at Microsoft.Maui.Graphics.Platform.UIImageExtensions.ScaleImage(UIImage target, Single maxWidth, Single maxHeight, Boolean disposeOriginal)
   at Microsoft.Maui.Graphics.Platform.PlatformImage.Downsize(Single maxWidth, Single maxHeight, Boolean disposeOriginal)
   at MauiCameraSettings.Helpers.ImageHelper.ResizeImageAsync(MemoryStream memStream, String imageType, Int32 resizeValue, Int32 compression, Boolean restoreExifOrientation, Boolean forceMainThread) in /Users/brentparish/src/maui-camera-settings/MauiCameraSettings/MauiCameraSettings/Helpers/ImageHelper.cs:line 74

[NirmalKumarYuvaraj]

This issue has been verified in Visual Studio Code 1.101.2 with MAUI version (9.0.81). It can be reproduced on IOS platform. However it cannot be reproduced in Maui version v9.0.71

[sheiksyedm]

Regression PR : #26751