Thanks for all who help me to finish this App
First of all, I need to thank Microsoft, becasue they provide a lot of resources to help the developer such as Microsoft Virtual Academy and MSDN,etc.
Then I want to thank Bob Tabor because I learned how to write my first App and how to embed Flickr API into my App through Windows Phone 8 Development for Absolute Beginners in Channel9.
By the way, I found a lot of useful solutions for my problems from StackOverFlow; thanks to people who contribute their knowledges freely so that if I know how to solve a problem, I'll be glad to share my solution, too.
Flickr is a good resources for photos, thanks to them because it helps me to provide user an easy way to store and search desired photos.
Hm. I need to thank my son. He helped me to test this App and did some of the artworks. Some bugs and inconveniences were found by him, too.
Finally, thanks to all who let me feel warm during this period.