However, the alias for **readwriteimagevideo** seems to be not correctly interpreted, you can check this at 
http://docs.opencv.org/doc/tutorials/core/mat_the_basic_image_container/mat_the_basic_image_container.html#creating-a-mat-object-explicitly

And also, in the tutorial **Load, Modify, and Save an Image**, imwrite() function uses alias imwrite, that's why I say to keep consistency