I can't say on guinea pigs, because I've never had one, and have never really looked into their care requirements. Mice are pretty close to being identical to rats in their care. Like rats, they need mouse food, not food for other rodents. There are several rodent species that have specific requirements for their metabolism, and need a specifically formulated diet. Rats being one. The most popular rodents people keep as pets are guinea pigs, hamsters, and gerbils. A large number of people are still creeped out by mice and rats, even if they have other rodent species. I knew a woman who bred hamsters, but freaked at the sight of a rat or mouse. It's a psychological thing. Most likely a phobia. A friend who has become family of mine hates rats. He has a severe phobia of them. I don't know if it's something that is just part of his psyche or if he had a traumatic experience as a child, and I'm not about to ask. It's not my place to ask such a question. If he wants me to know he'll tell me.
As for their habitat, if you want to go with a wire cage that's a "rat city" like I have for mine ABSOLUTELY DO NOT GET ONE WITH THE BARS SPACED OVER ½ INCH. If you do, they WILL escape. Then you will spend the next 2½ hours moving furniture all over and chasing the damn rat all over the room trying to catch it. And if it's one that bites, like one of mine, you're pretty much screwed. Thankfully that wasn't the one that escaped, before I wised up. Wiley little critters. Sometimes a major pain in the butt too.
As for the pics, no, I didn't take them. They were just some of the absolute best ones I found on a google search for this blog post.