Is it legal to sell photocopies of autographs?

[Lyca]

I have some cool autographed photos, and last week I got new printer/scanner/copier and I was testing all the functions, I scanned one of my pics so I would have it on my pc, be able to show it off on my facebook and so on.. then I made a copy with some nice quality glossy photo paper just to see what the quality would look like and it came out almost exactly like the original.. My kids said do loads and put them on ebay.. I replied that I'm fairly certain that would be illegal, they said it would be fine as long as I listed them as, photo PRINTS of autographs.. or copy prints or something like that..

But surely the pics would be copyrighted image anyway?? a few of my friends say no, as these things are given away at conventions, meets and so on.. and there is no watermark or copyright symbol.. but I think that it sounds like a very dubious, dodgy, easy way to make money..

I'm not even bothered about making money this way tbh... if it was legal I'd maybe only sell a couple for a small price.. fans would like them I'm sure.. but really I'm just asking now because I'm sure I'm right but everyone else is saying I'm wrong and stupid for not doing it..
My kids don't want any money for themselves, they earn more than me lol.. They're grown.. I just call them kids because I'm still mum..