how to read first image from subfolders with same directory?

 I have database of iris segmentation a folder contain 241 subfolders (named from 1 to 241) each of them contain 5 images (named from Img_1_1_1 to Img_1_1_5)and second subfolder's image named (Img_2_1_1 to Img_2_1_5) and so on ,please I need code to read the first image only from each subfolder and make same processing to them thanks