App Preview doesn't match the Browser Preview!!!

Hello everyone,

I ran into this problem that the app preview and the browser preview show very different things. Would anyone be able to tell me what the problem is?

I was making an HTML5 banner, and I've made the text just .png's because I the embed font option is all greyed out, did my research and found out that some things are just greyed out for HTML5 Banners. I know this isn't the most efficient way of doing things, if anyone could let me know that would also be greatly appreciated.

Much appreciated, thank you very much.

figure a (browser preview)

figure b (app preview)