Surendra, we will need a lot more information to help you out with this. How are you adding the image? In your custom code are you first uploading the file into a binary object or to the Kentico server then adding it to the database? Are you using some kind of image upload control in your .NET code?
There are additional steps to adding an image vs just saving data into Kentico. Some ideas on what you have done in your custom code could allow us to help you better.