你可以通过隐藏附件本身来隐藏 "MISSING "图片。但是，如果隐藏附件很麻烦，因为附件应该在以后显示，你可以为预览目的创建一个动画，在动画中隐藏附件，并在预览视图中的高轨道上播放隐藏附件的动画。在下图中，设置中显示了 "MISSING "图像，但通过播放有隐藏护目镜的附件键的动画，在没有 "MISSING "图像的情况下对Spineboy进行预览。

You can hide the "MISSING" image by hiding the attachment itself. However, if it is troublesome to hide the attachment since the attachment should be displayed later, you can create an animation for preview purpose, hide the attachment in the animation, and play the animation for hiding the attachment on a higher track in the Preview view. In the following image, the “MISSING” image is displayed in the setup, but the Spineboy is previewed without the “MISSING" image by playing an animation which has an attachment key that hides goggles.

以上希望能为您提供参考。
I hope this will help you.