IOS获取网络图片属性

- (CGSize)getImageSizeWithURL:(NSURL *)url
{
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((CFURLRef)url, NULL);
CGFloat width = 0.0f, height = 0.0f;

if (imageSource)
{
CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, NULL);

if (imageProperties != NULL)
{
CFNumberRef widthNum  = CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelWidth);
if (widthNum != NULL) {
CFNumberGetValue(widthNum, kCFNumberFloatType, &width);
}

CFNumberRef heightNum = CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelHeight);
if (heightNum != NULL) {
CFNumberGetValue(heightNum, kCFNumberFloatType, &height);
}

CFRelease(imageProperties);
}
CFRelease(imageSource);
NSLog(@"Image dimensions: %.0f x %.0f px", width, height);
}
return CGSizeMake(width, height);
}