Why do old cameras have awful pic quality although the MP is higher then my phone?

So I have an old compact camera with 12.1 MP, which i got around 2010 or 2011. I recently got a charger to charge my old camera to try out cuz I thought it would have a better quality then my iPhone 7 Plus (12MP). But when I tried taking pictures with my old camera it looks like it only have 1MP. I'm so confused because the MP are the same yet the photo quality has such big difference. Any idea why?

How can i convince my parents to buy me a new phone?

Right now i have an iPhone 6 and it is getting really old and i hate it. I want to pre-order the new Samsung Galaxy Note 8 but they won't let me. They have the money, they are just being stupid and cheap. I really want a new phone. I have had the iPhone 6 since 2014 when it first came out. How can i convince them to let me buy it? I hate them for this, they never buy me anything.

Can my old carrier unblock my phone even though it's not activated?

Today i called sprint and i told them to unblock my phone since the iPhone has already been paid and i have more than 50 days with them so they told me that they were gonna unblock it between 48-72 hours so i moved to cricket the same day i called sprint and cricket gave me a free phone while the iPhone 7 gets unblocked but my question is will they still unblock it even though i don't have my iPhone activated anymore and i moved to another carrier?

Is the iPhone SE as safe as the iPhone 7?

Is the security as good as on the iPhone SE as the iPhone 7? I'm thinking of getting a new phone and like the SE but don't know if it's as secure as the iPhone 7.

What should I decide in this situation?

My phone contract for my Samsung Galaxy S6 ends on this coming Monday. I've been using this phone for the past 2 years. My dad says that I should stick with the same phone but get a sim only deal with plenty of mobile data. The thing is, I would but the S6 has such a terrible battery life even if I use it in power saving mode. Plus I checked the sim only deals and some of them were a ripoff but some were reasonable. But the reasonable ones are on a different carrier and I don't want to switch. I saw a special offer deal for an iPhone 7 (32GB) for 20GB of mobile data, unlimited calls and text for £39 per month with a £49.99 upfront cost. Which one would you get in my situation, a sim deal with the same phone I've used for the past 2 years, or the iPhone 7 deal?

What is this iPhone app called?

A few years ago I had this app on my iPhone which I unfortunately no longer have. I really want to re-download it. The app let you use your camera roll, to upload pictures and it would show them in various scenarios. For example, you could upload a picture of yourself and one filter would make it appear as if your face was on a movie theatre screen. Does anybody know what this app is called?