在UIImage实例上使用size属性。有关详细信息，请参阅文档。

有很多有用的解决方案，但没有简单的扩展方法。下面是用扩展解决这个问题的代码:

extension UIImage {

    var getWidth: CGFloat {
        get {
            let width = self.size.width
            return width
        }
    }

    var getHeight: CGFloat {
        get {
            let height = self.size.height
            return height
        }
    }
}

在UIImage实例上使用size属性。有关详细信息，请参阅文档。

UIImage *img = [UIImage imageNamed:@"logo.png"];

CGFloat width = img.size.width;
CGFloat height = img.size.height;

let heightInPoints = image.size.height
let heightInPixels = heightInPoints * image.scale

let widthInPoints = image.size.width
let widthInPixels = widthInPoints * image.scale

UIImageView *imageView = [[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"MyImage.png"]]autorelease];

NSLog(@"Size of my Image => %f, %f ", [[imageView image] size].width, [[imageView image] size].height) ;