如何使用col-md-4类创建一行我可以放置完全相同尺寸的图像？

i have to make two rows in my webpage to show 4 images per row. but when I put the images into the code, they show in different dimensions even when i have resized them for same dimensions. please help. the code for the row is given below:i have to make two rows in my webpage to show 4