Hi, it was set to Iphone 5 Tall 9:16. It seems if I set it to Iphone4 tall, it picks up since there are specified pixels. However, I am still confused on how to find the right image size for tk2dCamera..
For example, now the Native Resolution is 960 x 640 with Preview Resolution of 640x960. In photoshop, I created a test background with a solid color of size 640x960. The image resolution is set at 300 pixels per cm. On the tk2dCamara, the resolution per meter is 1. It seems like as I set the image resolution higher, the image is smaller when I add it to the game using sprite collection.
Update: I set the camera and sprite collection to 1 pixel per meter with images scale at Vector3.one. The preview window looks correct, but when I press the play button, the images are zoomed in (i.e. the become a lot bigger).
Solved. Screen scales have to be Vector3.one also...