Anytime greeting is ready for your website user. Time Based Greeting
Q1) Where Do I keep my images?
Ans:Keep your images in the same folder where you have your wordpress installation.Dont put your images in any of the subfolders.Just paste it there directly in the folder of your wordpress installations.
Q2) What time does plugin takes as base?
Ans:Plugin takes users time and not your time.If a user who visits your website has different time zone than yours will see messages and images according to its own time and not your time.