Here are the basic steps to insert a RadImageEditor control on your page:
Create a new ASP.NET AJAX - enabled web site.
Add a RadScriptManager or the standard ASP ScriptManager to the page - this step is mandatory if you are using ASP.NET AJAX controls.
Drag a RadImageEditor from your VS Toolbox and drop it on the page.
Right-click on the inserted RadImageEditor control and select properties.
Set ImageUrl property from the Properties tab to point to an image to be loaded, please note that the image must be located in a folder accessible from the application.
If you are not creating a Telerik UI WebSite you should add the RadImageEditor HttpHanlder from its smart tag
You can additionally configure where the control should store its cache and the position of the status bar using corresponding properties – ImageCacheStorageLocation, StatusBarMode.
Save the page and run it in the browser.