With the help of following code you can divide UIImage into equal parts w.r.t number of row and number of column.
Create a category of UIImageView and UImage and write the following method respectively in them.

-(NSArray *)divideImageViewInImage:(int)row column:(int)column{
    NSMutableArray *imageArray = [NSMutableArray new];
    CGFloat width,height;
    width = self.frame.size.width/column;
    height = self.frame.size.height/row;
    CGFloat x = 0,y = 0;
    for (int i = 0; i < row; i++) {
        for (int j = 0; j < column; j++) {

            CGRect frame = CGRectMake(x, y, width, height);
            [imageArray addObject:[self.image imageFromImageView:self rectFrame:frame]];
            x = x + width;
        }
        x = 0;
        y = y + height;
    }

    return imageArray;
}
-(UIImage *)imageFromImageView:(UIImageView *)imageView rectFrame:(CGRect)frame{
    UIGraphicsBeginImageContextWithOptions(frame.size, imageView.opaque, 2.0);
//    UIGraphicsBeginImageContext(frame.size);

    CGContextRef c = UIGraphicsGetCurrentContext();

    CGContextConcatCTM(c, CGAffineTransformMakeTranslation(-frame.origin.x, -frame.origin.y));

    [imageView.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage * img = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();
    return img;
}

Happy coding :)