Interface ImageBitmapLoader

Note that Texture.flipY and Texture.premultiplyAlpha with ImageBitmap are ignored. ImageBitmap needs these configuration on bitmap creation unlike regular images need them on uploading to GPU. You need to set the equivalent options via ImageBitmapLoader.setOptions instead. Refer to WebGL specification for the detail.

WebGL / loader / ImageBitmap

// instantiate a loader
const loader = new THREE.ImageBitmapLoader();
// set options if needed
loader.setOptions( { imageOrientation: 'flipY' } );
// load a image resource
loader.load(
    'textures/skyboxsun25degtest.png', // resource URL
    function ( imageBitmap ) { // onLoad callback
        const texture = new THREE.CanvasTexture( imageBitmap );
        const material = new THREE.MeshBasicMaterial( { map: texture } );
    },
    undefined, // onProgress callback currently not supported
    function ( err ) { // onError callback
        console.log( 'An error happened' );
    }
);