Yes there is, I can't remember what it's called though. I found it by googling basically the exact question you're asking. It was a 3rd party app you had to download and then log into your snapchat account through that, you could then open the snap and screenshot it and it wouldn't send them any notification about it. I think there are actually several of these third party apps, the one I used in the past I think was called something along the lines of snapsave or savesnap or snapsaver... I'm not 100% sure though, it's been awhile.