Hello Franz 🤙 . The things you publish with your npub is portable to many other clients, each one works its own way to display your content and its media, —text, photo, videos, etc. This for example is not precisely "an instagram like" client; rather simply the interface of the browser-based nostr client, nostrudel, listing my notes in the format of "images only" (you could check yours if you go to https://nostrudel.ninja/#/u/npub1r090w6fetmz496j7z4p844u04hmqwe2rmulel57jjqzhwcsm2zsq6t2w5a/notes?view=images ). https://image.nostr.build/379014bd5061228d7a793250a0e578f38bf6671371491f9e1ba1865393bf4abe.png I'd say it looks even better than instagram as it displays better the proportions of the media. 

That being said, you can feel free to write and upload media in the nostr app you feel more comfortable with, and your followers will use the favorite of theirs to check your content 🤙 ; all this of course possible to the hard work of our lovely zen not ranting at all developers. 🐸 🫡.