Oh nostr:nprofile1qqs9ywrudwvucs42c5v3dvyt0dga9wkalsvl9wsgmq4yssegf8dalvspp4mhxue69uhkummn9ekx7mqpz4mhxue69uhhg6t8wvhxummnw3erztnrdakszxthwden5te0wdjkuerfwshxummnvekxzun99e3k7mgh6uj5x had the same issue with the white background. I'm guessing you're on Damus. I think if you post in that link directly it'll keep the transparent background.