UIWebview iPhone loading bundle resources

I'm trying to load images from the bundle to a uiwebview.

the code i'm currently using is

NSString *path = [[NSBundle mainBundle] bundlePath];
NSURL *baseURL = [NSURL fileURLWithPath:path];
[webView loadHTMLString:htmlString baseURL:baseURL];

when i open the view the 开发者_运维百科application closes and opens safari and an error message pops with 'Safari cannot open the file. The error was: "file is directory".'

if i set the baseURL as nil then the page loads correctly (although without the images).

Any suggestions?

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Just installed the application onto an actual iphone - and it works correctly as expected, just in the iphone simulator UIWebView and bundle path doesn't work correctly.