A tricky css thing in Safari, solved by a recent comment on an 8-year-old question on Stack Overflow. I have a strip of thumbnails in a div set to display: flex. Looks fine in FF & chromium. In Safari they're all stretched too tall. A S.O. user points out that "When you set display flex, it also assign some other properties to it's children. Initial value of flex childrens for align-items is stretch," whereas in other browsers it is not set to stretch. You just have to unset that or align-self: flex-start to each image.