SnapShot can suggest to the user to skip CrossOrigin

[offtherailz]

When the snapshot contains images that require cross origin, the snapshot generation becomes complicated. But the preview is generated at full resolution and with the correct tiles. This can not be used via javascript because of security limitations (the canvas is tainted, see this: https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image)

But there is a trick. The user can right-click on the preview and click "Save Image as". So we can see if the canvas is tainted, and if it is, suggest the user to do the trick. "The Save functionality is limited because of security limitations, for better result please right click on the Preview and select "Save Image as..."

[offtherailz]

Something like this: