add screenshots

README.md

@@ -1,4 +1,6 @@
 # myBookShelf
 This is a Free Pascal/Lazarus project to keep all your ebooks (and pdfs) organized in an iBook like graphical interface.
 
-![Screenshot](/screenshot/mybookshelf_screenshot1.png?raw=true "GTK Screenshot")
+![Screenshot](/screenshot/mybookshelf_screenshot2.png?raw=true "GTK Screenshot")
+
+![Screenshot](/screenshot/mybookshelf_screenshot3.png?raw=true "GTK Screenshot")