Accessing to the packed sprites

A. How can I access to the sprites in script?

B. When building a project, all original sprite images(textures) which are going to get packed are excluded? If so, is it okay to put the original images under the Resource folder?
And if the original sprite textures are assigned to any prefabs/objects, doesn't matter?

C. Do I have to consider something for accessing to sprites that have packed already in script?

 

No, putting sprites in Resources prevents them from being packed.

--Eric