Mail app spam attachments

Hi, I was scrolling through my email on the mail app on my iPhone SE and accidentally tapped one of those spam bitcoin emails which opened it. I get those frequently, but this one had a .jpg attachment with it. The message looked like text (the old blackmail scam) and I trashed it before I could really see what was in it or attached.

So here's my question, would the mail app download a .jpg attachment automatically? And if so, could that have included a virus that would affect an iPhone? Is there any need to reset the phone?