The problem is that the image registry only gives out Images. You can't ask it for an ImageDescriptor.

问题是图像注册表只提供Images—无法要求它提供ImageDescriptor。

youdao

To do this, JFace provides ImageDescriptor, which is a lightweight object that doesn't store the image itself, but can create a particular image on demand.

为此，JFace提供了ImageDescriptor(请参阅参考资料)，这是一个轻量级对象，它不存储图像本身，而是可以按需要创建特定的图像。

youdao