For obvious reasons, I don't want to post her face on this site, but I'm hoping this is the right board to ask about digital image quality. I wouldn't expect anyone on adv or r to get back to me in a timely manner; I'm sure this forum is more generally knowledgeable on what I need answered.

to the point:
So far the best quality scanner I've found publicly available is at Walmart, but I went to send the scan to the monument maker today and realized it was a .jpg. I had no control over the scanner itself and had to use their default settings, so this is what I have. (I believe it was an epson perfection with dpi 9600x4800, and I had to hope they scanned at max settings by default)

My grandparents and I agreed on an older photo of her before she got sick, but having to blow up her face a bit has made it blurry, obviously. And then I remembered the meme I see in the ad banner for this board "using .jpg's in a high quality photo board" or some such, and so I did some research and found .png's have superior quality?

I also noticed the scan I did on my grandparents' HP officejet actually appeared brighter and more vivid than the epson perfection at walmart, though it was more pixelated.

FINALLY, and this may intrigue someone out there because to me it just seems really bizarre and unexpected, the scan on my grandparents' officejet and the scan on the walmart epson perfection have her face proportioned differently. It's very, very subtle but when placed side-by-side on the screen and compared with a straightedge (I used the greenshot cursor/line) I can see that the epson scan has her face stretched overso slightly, at least I think it's the epson scan that is less accurate to the original... enough so that the top of her hair lines up b/n the two pics but her chin does not.

Can someone help clarify or make recommendations on what the ideal settings, software, and hardware are for a "perfect" scan? I'm trying not to buy a scanner, but I will if I have to. Thanks.