fix Bug

[problem]
Don't change display image at index page after edit image file.
(Index page can display new image after reload)

[cause]
Index page display old image file's chache.
Because old/new images have same file name(map's id).

[changes]
- Unuse map's id for image name.
- Use unique id for image name.
- Impl getImageName function from map's id.