Attach (recommended) or Link to PDF file here:
https://guichet.public.lu/dam-assets/catalogue-formulaires/tva/tva-option-aic-pers-morales/tva-option-aic-pers-morale-DE.pdf

Configuration:
- Web browser and its version: Firefox Nightly 91.0a1 (2021-06-26) (64-bit)
- Operating system and its version: Windows 10.0.19043.1052
- PDF.js version: N/A

Steps to reproduce the problem:
1. enableXFA in Firefox Nightly
2. Open form

What is the expected behavior? (add screenshot)
Header image is scaled properly
![image](https://user-images.githubusercontent.com/7104454/123525954-905d1f00-d6a2-11eb-840e-be30eee395e1.png)

What went wrong? (add screenshot)
Image is scaled to fit
![image](https://user-images.githubusercontent.com/7104454/123525957-96530000-d6a2-11eb-9991-bf7f37c6f1a5.png)


Object.assign(style, this.fill[$toStyle]());
    }
    if (this.corner.children.some(node => node.radius !== 0)) {
      const cornerStyles = this.corner.children.map(node => node[$toStyle]());
      if (cornerStyles.length === 2 || cornerStyles.length === 3) {
        const last = cornerStyles[cornerStyles.length - 1];
        for (let i = cornerStyles.length; i < 4; i++) {
          cornerStyles.push(last);
        }
      }
      style.borderRadius = cornerStyles.map(s => s.radius).join(" ");
    }
    switch (this.presence) {
      case "invisible":
      case "hidden":
        style.borderStyle = "";
        break;
      case "inactive":
        style.borderStyle = "none";
        break;
      default:
        style.borderStyle = edgeStyles.map(s => s.style).join(" ");
        break;
    }
    style.borderWidth = edgeStyles.map(s => s.width).join(" ");
    style.borderColor = edgeStyles.map(s => s.color).join(" ");
    return style;
  }
}
class Break extends XFAObject {