Not sure if this requires people that are tech savvy
If a site is dodgy or bad, that's usually because the people running it are dodgy. If a site itself would be 'dodgy', then I'd imagine it would be riddled with bugs, glitches, and more, because it wouldn't function properly.
Still, to answer your question:
I don't have experience with the site. If I would have a bad feeling about a site, I wouldn't even think about ordering anything. A site can look extremely professional, while actually scamming people. So you even have to look out for company sites that don't seem dodgy, is what I'm saying.
I can't name a few sites which do actually seem legit and do similar things, but I know there are quite a few out there. In fact, I would suggest you take a look at printer shops or certain stores to see if they do anything special printing on bags or the like.
I found out a store chain here (similar to Best Buy, I suppose?) actually has the option to use a machine where you can select your own picture and have it printed not only on paper, but canvas, bag, and a cup. Not sure if they still do it, but they used to