message: Fix the FireFox cached image issue
diff: @@ -33,6 +33,16 @@ export default class ImageResource extends BaseImageResource
  super(source);
  + // FireFox 68, and possibly other versions, seems like setting the HTMLImageElement#width and #height
  + // to non-zero values before its loading completes if images are in a cache.
  + // Because of this, need to set the `_width` and the `_height` to zero to avoid uploading incomplete images.
  + // Please refer to the issue #5968 (https://github.com/pixijs/pixi.js/issues/5968).
  + if (!source.complete && !!this._width && !!this._height)
  + {
  + this._width = 0;
  + this._height = 0;
  + }
  +
  /**
  * URL of the image source
  * @member {string}
  