Matlab - Opening more then one image extension - working with images

I need open and put in the same vector .jpg images and .bmp images. I can open or .jpg or .bmp, but i need to open both.

This is my code:

    image_folder = 'C:\Users\Marco\Desktop\teste';    
    filenames = dir(fullfile(image_folder, '*.jpg')); 
    total_images = numel(filenames); 

    for n=1:total_images
    images{n} = imread(sprintf('color%03d.jpg',n));  
    end;

(in this example i open jpgs but i need to open .jpg And .bmp )