The Kendo UI ImageEditor's SaveAs.ProxyURL does not accept a string using Razor Syntax.
Like the jQuery configuration, the ProxyURL should accept string URLs.
Utilizing the Kendo UI ImageEditor's setOptions method, configure the proxyURL with jQuery:
$(function () {
var imageEditor = $("#imageEditor").data("kendoImageEditor");
imageEditor.setOptions({
saveAs: {
fileName: "ImageEditorFile.png",
forceProxy: true,
proxyURL: "Home/SaveProxyURL",
}
});
});