iOS 图片压缩

- (UIImage *)fitImageSizeWith:(UIImage *)img
{
    float destWith = 600.0;
    float destHeight = 600.0;
    
    CGSize itemSize = CGSizeMake(destWith, destHeight);
    UIGraphicsBeginImageContext(itemSize);
    CGRect imageRect = CGRectMake(0, 0, destWith + 1, destHeight);
    [img drawInRect:imageRect];
    UIImage *newImg = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return newImg;
}