Working around incompatible pointer via NSImage and NSStatusBar

I'm giving a status bar item an image through NSImage. I'm running into were the app builds and opens in the status bar, but the image I want dosen't display. I receive a warning saying "Incompatible pointer types sending 'NSString' to parameter of type "NSImage". It's displayed to this code...

- (void)setImage:(NSImage *)image{
 [statusItem setImage:@"cargo-menu.png"];
}
-(void)setAlternateImage:(NSImage *)image{
 
}