@(Html.Kendo()
                .EditorFor(m => m.HtmlContent)
                .Encode(false)
                .Tools(t => t.BackColor().InsertImage())
                .ImageBrowser(imageBrowser => imageBrowser
                    .Image("Image", "ImageGallery")    
                    .Read("Read", "ImageGallery")
                    .Create("Create", "ImageGallery")
                    .Destroy("Destroy", "ImageGallery")
                    .Upload("Upload", "ImageGallery")
                    .Thumbnail("Thumbnail", "ImageGallery")
                    )   
                )

Contoller methods:

public JsonResult Read(string path)
{
var files = _imageGalleryService.GetImageListForFolder(ClientId, null)
								.Select(f => new
									{
										Name = f.FileName,
										Type = "f",
										size = f.Size
									});

return Json(files, JsonRequestBehavior.AllowGet);
}

[OutputCache(Duration = 3600, VaryByParam = "path")]
public ActionResult Thumbnail(string path)
{
	var image = _imageGalleryService.GetImageByName(ClientId, path);
	//Response.AddFileDependency(fileName);
	const string contentType = "image/png";
	var desiredSize = new ImageSize
		{
			Width = ThumbnailWidth,
			Height = ThumbnailHeight
		};

	var stream = new MemoryStream(image.Image);

	return File(_thumbnailCreator.Create(stream, desiredSize, contentType), contentType);
}

[OutputCache(Duration = 360, VaryByParam = "path")]
public ActionResult Image(string path)
{
	var image = _imageGalleryService.GetImageByName(ClientId, path);
	return File(new MemoryStream(image.Image), image.MimeType);
}