Teddan as far as I understand, it's rather difficult to fix it in Flarum and is rather work for an extension. The best approach is to somehow store in the DB the dimensions of the images and then when loading the page to load these dimensions and use them in CSS to tell the browser to automatically reserve the needed space, based on the ratio.
BTW, the problem also happens on Safari for Mac though. I've also reproduced it on other browsers and OS-es but it happens more rarely, I guess they have better caching or algorithms for rendering. However on Safari for iOS it's extremely annoying.
As a side note, I think not much of the developers use Apple devices, at least that's my feel. I guess developers tend to prefer Linux, Android, etc. and web-developers hate Safari which is why they develop mainly for Chrome. I have no high hopes this will ever get fixed. I reported it to Apple, so that they make their browser better but... I'm not holding my breath for Apple to react to such a feedback... And Flarum devs are busy and doing all these great things on Flarum for free, so I wouldn't expect for them to purchase Apple devices and start testing and developing for Apple specifically, so not much can be done. Maybe if there are more people who are interested in this being fixed, we can commission a paid extension? I'm ready to pay for something like that although not much. But if there are more people interested, we can start a campaign?
