UTexture2D identifier is undefined

[Shadowriver]

You need to forward declare the class like this:

UPROPERTY(BlueprintReadWrite)
class UTexture2D* sourceImage;

or put class UTexture2D; before the struct. Then in cpp file that gonna use this struct you include “Engine/Texture2D.h”.

Normally you would do include in header file and that it, but this convention of using forward declarations in entire UE4 prevents circular references to occur. you can read about it more here:

Forward declaration

A new, community-hosted Unreal Engine Wiki