据说iOS7.0之后会遇到这种错,可我又不知道错在哪,怎么搞,求解?

Question

<Error>: CGBitmapContextCreate: unsupported parameter combination: set CGBITMAP_CONTEXT_LOG_ERRORS environmental variable to see the details
Dec 27 16:20:34  AppPink[33402] <Error>: CGContextDrawImage: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Dec 27 16:20:34  AppPink[33402] <Error>: CGBitmapContextCreateImage: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.

百度了好多都是英文的,看不太懂.....