Select a specific image in a face recognition algorithm

Hello. I am using this algorithm for face recognition: Face Recognition

I made some modification so i have now a new GUI, buttons and 2 axes.

My current code is something like this:

I have a Load Database button and this is the code used for loading it.

 function load_database_Callback(hObject, eventdata, handles)
 load_database

My next button is Search

 function search_Callback(hObject, eventdata, handles)

 w=load_database();
 ri=round(400*rand(1,1));
 r=w(:,ri)
 v=w(:,[1:ri-1 ri+1:end]);

 N=10;

 O=uint8(ones(1,size(v,2))); 
 m=uint8(mean(v,2));             
 vzm=v-uint8(single(m)*single(O));

 L=single(vzm)'*single(vzm);
 [V,D]=eig(L); 
 V=single(vzm)*V;
 V=V(:,end:-1:end-(N-1));      

 cv=zeros(size(v,2),N); 
 for i=1:size(v,2);
    cv(i,:)=single(vzm(:,i))'*V; 
 end
 imshow(reshape(r,112,92));
 axes(handles.axessearcheigen); 
 p=r-m;                           
 s=single(p)'*V;
 z=[];
 for i=1:size(v,2)
    z=[z,norm(cv(i,:)-s,2)];
    if(rem(i,20)==0),imshow(reshape(v(:,i),112,92)),end;
    drawnow;
 end

 [a,i]=min(z);
 imshow(reshape(v(:,i),112,92));
 axes(handles.axesfoundeigen);

I modified some code to show the pictures in axes. The code above and the Load and Search buttons work.

This is where i am stuck: I made a Open Image Button so i can open a specific image.

:

This is the code for the Open Image button

 function open_image_Callback(hObject, eventdata, handles)

I tried this to open an image and put it in axis, but it does not work

 function open_image_Callback(hObject, eventdata, handles)
 global filename pathname I
 [filename, pathname] = uigetfile('*.pgm');
 axes(handles.axessearcheigen)
 imgpath=STRCAT(pathname,filename);
 I = imread(imgpath);
 imagesc(I),axis off,colormap(gray(256))

The big question is: How i make this button to open a specific picture, and then replace somehow the:

 ri=round(400*rand(1,1));

or whatever needs to be modified.

TL;DR: I want to open and search a specific picture, not a random one.

Thanks.