1) Open the solution explorer add the image (for e.g GenericPrint16.png) in the images subfolder. 2) Change the image name in the 'Config.esriaddinx' file.3) Rebuild the solution and close the application.4) Now go to the debug>bin folder and rename the .esriAddIn to .zip extension.5) Open the zip file and add the image (GenericPrint16.png) in the images folder.6) Close the folder and rename the .zip file to .esriAddIn.7) Double click the .esriAddIn file to install the addin.8) Open ArcMap and follow the procedure to drag and drop the add in button on the toolbar and you should be able to see the print image on the button.The disadvantage is that if we rebuild the solution the image will reference back to the old image and will not show the new image. So every time we rebuild it we have to repeat the steps specified above.