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Unable to edit base64 image on RadEditor using ImageManager


Product RadEditor for ASP.NET AJAX


The image manager of RadEditor can work with physical images only. That is why if you select a base64 image in the content area and press the Image Manager you will get the following error: HTTP Error 414. The request URL is too long.

See in the Solution section below how you can solve it.

Error Message

HTTP Error 414. The request URL is too long error is thrown when loading a base64 image in RadEditor ImageManager dialog.


The reported HTTP Error 414. The request URL is too long happens because the Image Manager does not support base64 images and when you call it with a base64 src, the URL path of the dialog handler becomes too long and the server rejects the request.

The solution is to override the setUrl method of RadWindow to check for base64 image path and to cut it down:

    Telerik.Web.UI.Window.LightweightView.prototype.setUrl = function (url) {
        var frame = this.ui.contentFrame;
        if (!frame) return;
        if (url.length < 2000) {
            frame.src = url;
        else if (url.indexOf('base64') > 0) {
            alert("The Image Manager can operate only with physical files");
            frame.src = url.substring(0, url.lastIndexOf('PreselectedItemUrl'));

        this.setContentFixedHeight(this.window.get_height(), this.ui.content);

<telerik:RadEditor runat="server" ID="RadEditor1"></telerik:RadEditor>

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