From MATLAB to C#. C# programm has lags

I created some function in Matlab. This function image grayscale picture from .mat-file.

I have this command in MATLAB.

figure, imshow(Image_uint8);

I created .dll from this function. My small console programm on C# work, but I have big lags when I want to know point and his value of picture. It`s more than some lags.

C#

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            Test11.step7();

        }
    }
}

using MathWorks.MATLAB.NET.Utility;
using MathWorks.MATLAB.NET.Arrays;
using step0;

namespace ConsoleApp1
{
    class Test11
    {
        public static void step7()
        {
            Class1 ojb = new Class1();
            MWArray output1 = ojb.step0();
            Console.WriteLine("Output ~\n" + output1);
            Console.ReadKey();
        }
    }
}

MATLAB

function [pname_save] = step0()

[fname_open, pname_open] = uigetfile('*.asd','Select the .asd file');
if fname_open ~=0
    fullname = strcat(pname_open,fname_open);
    cd (pname_open);
else
    fullname = null;
end

...

    figure, imshow(Image_uint8)

    %save file
    result = regexprep(fname_open, '\.[^\.]*$', ''); 
    pname_save = [pname_open name_out];
    cd (pname_save);
...

fclose (fid); 

end