//从路径中获得完整的文件名 （带后缀） 对从相册中取出的图片，视频都有效。
NSString *fileName = [filePath lastPathComponent];
//获得文件名 （不带后缀）
NSString *fileName1 = [filePath stringByDeletingPathExtension];
//获得文件的后缀名 （不带‘.‘）
NSString *suffix = [filePath pathExtension];
// 拿到图片名字 亲测只对图片有效
NSURL *refURL = [info valueForKey:UIImagePickerControllerReferenceURL];
define the block to call when we get the asset based on the url (below)
ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *imageAsset)
{
ALAssetRepresentation *imageRep = [imageAsset defaultRepresentation];
DNLog(@"[imageRep filename] : %@", [imageRep filename]);
};
// get the asset library and fetch the asset based on the ref url (pass in block above)
ALAssetsLibrary* assetslibrary = [[ALAssetsLibrary alloc] init];
[assetslibrary assetForURL:refURL resultBlock:resultblock failureBlock:nil];
[picker dismissViewControllerAnimated:YES completion:nil];
原文：http://www.cnblogs.com/soulDn/p/5703029.html