ERROR DOMException: Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases may not be exported.

I used the following tag to load the image:

```

```

I used the following function in my component to save the return Url from `getAnnotatedImage()` function call:

```
save() {
let saved = this.annotator.getAnnotatedImage('image/png');
if (saved)
this.mySavedImage = saved;
}
```
but it failed with the following error:

```
ERROR DOMException: Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases may not be exported.
at AiaImageAnnotatorComponent.getAnnotatedImage (http://localhost:4200/vendor.js:71813:28)
at AppComponent.save (http://localhost:4200/main.js:168:36)
at AppComponent_Template_button_click_171_listener (http://localhost:4200/main.js:493:147)
at executeListenerWithErrorHandling (http://localhost:4200/vendor.js:26822:16)
at wrapListenerIn_markDirtyAndPreventDefault (http://localhost:4200/vendor.js:26864:22)
at HTMLButtonElement. (http://localhost:4200/vendor.js:60166:38)
at ZoneDelegate.invokeTask (http://localhost:4200/polyfills.js:412:35)
at Object.onInvokeTask (http://localhost:4200/vendor.js:44161:33)
at ZoneDelegate.invokeTask (http://localhost:4200/polyfills.js:411:40)
at Zone.runTask (http://localhost:4200/polyfills.js:180:51)
```

I tried to save when it has not been edited, it failed the same way. Is the save function implemented in this tool?

首先复现 AppComponent.save()，该方法会调用 AiaImageAnnotatorComponent.getAnnotatedImage('image/png')，并检查与该入口点关联的 canvas 导出路径。确定未编辑图像的预期行为，以及库是否处理了报告的失败；当预期的保存行为已经确定并验证后，即表示完成。

由索引模型根据 Issue 内容生成。