Loop for open files / extracting image data and saving them in a matrix file

I have an image database, in the form of files (106 files and each file contains 48 images)

I want to generate a matrix for the database (db.mat)

I want my program to read each folder (from 001 to 106) and take the data (mydata) and save them all to a db.mat file

here is my program :

clear all;
clc;
cd D:\001\FT-2BU\FT-2BU
s = '';
str1 ='00';
str2 ='0';
for i=1:106
	if i<10 
	s=strcat(str1,i);
    bmpFiles = dir('*.bmp'); 
    numfiles = length(bmpFiles);
    mydata = cell(1, numfiles);
    for k = 1:numfiles 
    mydata{k} = imread(bmpFiles(k).name);
    end
    save mydata;
  
    elseif i<100
	s=strcat(str2,i);
    bmpFiles = dir('*.bmp');
    numfiles = length(bmpFiles);
    mydata = cell(1, numfiles);
    for k = 1:numfiles 
    mydata{k} = imread(bmpFiles(k).name); 
    end
    save mydata;
    
    else
    s=i;
    bmpFiles = dir('*.bmp');
    numfiles = length(bmpFiles);
    mydata = cell(1, numfiles);
    for k = 1:numfiles 
    mydata{k} = imread(bmpFiles(k).name); 
    end
    save mydata;

    end
end