Hello Senthil,
You have found a help article which applies to RadSpell Classic only, but the solution is not applicable for RadSpell for ASP.NET AJAX.
You can see an example of RadSpell rendered as ImageButton at
http://demos.telerik.com/aspnet-ajax/spell/examples/whatsnew/defaultcs.aspx.
Here is an example:
Kind regards,
Rumen
the Telerik team
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