Phew!!! Another error that almost made me crazy!!! Last time I encountered almost the same error:
[function.move-uploaded-file]: failed to open stream: Permission denied
but this time error was
Warning: imagejpeg() [function.imagejpeg] … cannot open file for writing…
I had the right intuition… same solution… FILE PERMISSION so please check your folder / subfolder’s permission and set it to 777!!!
Goodluck!