圆角，图片相关

#pragma mark -
- (UIImage *)resizeImage:(UIImage *)image size:(CGSize)size
{
    UIGraphicsBeginImageContextWithOptions(size, NO, UIScreen.mainScreen.scale);
    CGRect imageRect = CGRectMake(0.0, 0.0, size.width, size.height);
    [image drawInRect:imageRect];
    UIImage *retImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return retImage;
}

- (UIImage *)blankImage
{
    CGSize size = CGSizeMake(25.f, 25.f);
    UIGraphicsBeginImageContextWithOptions(size, YES, 0);
    [[UIColor whiteColor] setFill];
    UIRectFill(CGRectMake(0, 0, size.width, size.height));
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}