z索引在悬停与引导img响应类

Newb here. I am building a site, and on this site I am displaying overlapping images. Therefore, I am using the z-index on hover so that the behind image comes forward when hovered over. However, I am also using bootstrap and the img-responsive tag and when I hover, the image flickers and then disappears. How can I fix this? Is it possible to handle this in only HTML/CSS, no Java?Newb here. I am building a site, and on this si