Firefox 45.4.0 (ESR) render problem

[patdavid]

Per @McCap on discuss, FF 45.4.0 does something strange with <figure> tags class big-vid

https://discuss.pixls.us/t/aligning-images-with-hugin/2609/18

In the style for p img, figure img there are two rules for width (yes, it says mad-height, i've already addressed this):

p img, figure img {
    width: 100%;
    width: initial;
    max-width: 100%;
    mad-height: 100vh;
    height: auto;
    margin: 0 auto 0.5rem auto;
}

without the width: initial the image renders fine, but I haven't had a chance to check it against a backstop render to see how disruptive it might be. I'll try to fix it this weekend.