Texture2D.LoadImage texture format override problem

[ArtyBrest]

Hi.
I use LoadImage() to work with external textures (JPG and PNG files) in my project. It has a problem with texture format preserving. For example I have 8-bit JPG (or PNG) texture (gray) and I want to upload it to Alpha8 format texture using next piece of code:

Texture2D outTexture = new Texture2D( 1, 1, TextureFormat.Alpha8, false, true );
if ( outTexture.LoadImage( atlasRawBytes.bytes, true ) )
{
    // use texture..
}

But texture format is overrided to RGB24 after loading. I can use LoadRawTextureData() to upload manually decoded jpg, but c# jpg decoding is too slow.
Could LoadImage() have a flag to preserve specified texture format or to respect file texture format?
Thanks.

[liortal]

You can see this behaviour is documented in the Texture2D.LoadImage docs (here: http://docs.unity3d.com/ScriptReference/Texture2D.LoadImage.html):

This function replaces texture contents with new image data. After LoadImage, texture size and format might change. JPG files are loaded into RGB24 format, PNG files are loaded into ARGB32 format. If texture format before calling LoadImage is DXT1 or DXT5, then the loaded image will be DXT-compressed (into DXT1 for JPG images and DXT5 for PNG images). If the platform is not able to perform runtime compression then false will be returned.

[zwcloud]

@liortal

You can see this behaviour is documented in the Texture2D.LoadImage docs (here: http://docs.unity3d.com/ScriptReference/Texture2D.LoadImage.html):

Unity should just assign alpha channel instead of changing the format.