[iPhone] big image become small image at first time load

Hi Team,

We have experienced in our website section loading (WP)slick slider with images. But it’s loading fine in the same size in desktop and android mobile when its load first time in the browser. And there is some problem with the image become bigger and changed to normal size for the first time load on the iPhone safari browser. Is there any specific reason, cache, or image size for this issue?