objective-C从远程地址获取图片并修改尺寸

NSData imageData = [[NSData alloc]initWithContentsOfURL:[NSURL URLWithString:imageURL]];

UIImage* image = [[UIImage alloc] initWithData:imageData];
// resize image
CGSize newSize = CGSizeMake(100, 100);
UIGraphicsBeginImageContext( newSize );// a CGSize that has the size you want
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
//image is the original UIImage
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
imageHeight = image.size.height;
[imageMain setImage:newImage];
[imageData release];
[image release];</pre>