The problem, GoodEnough, is that you aren't just saying "this is just for me, I'm fine with what you do." You've been trying to tell people here that their usage patterns are wrong. You've been making bad assumptions about what they value (no, we're not "megapixels are everything"). And frankly, you've been describing a very unusual, very niche approach to photography that doesn't gel with what most reasonable people consider when taking photos.
Most people have no reason to worry about downscaling or cropping. Most people have good reasons to take the highest-resolution photos they can, if just for the sake of futureproofing their collections. And of course, most people capture photos with the intent of keeping them for more than a year. If you can accept these truths, please reflect that in your posts -- otherwise, you deserve the criticism you're getting.
Honestly this thread is full of garbage. I've been trying to read this objectively, but you guys just are so full of ego it's caused all the problems in this thread.
1. OP came in here asking for how to turn down the resolution.
2. No one cared for to help him out. No instead we had to nitpick on the use "Android" and pwning him with the post from cronos. No one cared to ask what model, what software, what camera app.
3. The few people that did suggest an app, that was cool.
4. The rest of you nitpicked on his methods, using Google Photo backup, just getting a bigger SD card, etc.
Look, if the OP has a reasonable question, why not answer it? You can perhaps add some critique of his workflow and suggest an improvement, but his original request wasn't something completely outrageous.
With that said, I shoot full resolution on my cameraphone. Why not, storage is cheap, and even if storage is a problem, that's why I invested in a 128gb phone. I can also see why Google Photos isn't a solution. If I use a 32gb phone with no SD Card (ahem Nexus 5X), and with limited data, I would not want to rely on Google Photos. Heck I'm not even overly satisfied with Google Photos myself. It's often slow and clunky compared to the old AOSP browser. It will pause for a solid 5 seconds or so just to load your local folders. I can understand if the Online part is slow, but it's just poorly designed. Compare to other gallery apps like Smugmug which is fully cloud based, and you can see how slow Photos is. I can see why someone doesn't want to rely on cloud photos.
Finally, while I don't think 1-2MP is enough, it certainly is enough for viewing on Instagram and Facebook, which is what 95% of iPhone users and in general mobile users are doing. If that's all the OP is concerned with, then let him be. Just answer his question about how to obtain 2MP photos. I can't believe how this board is so toxic with people so insistent on how their workflow is the best and no one else can deviate. The only reason the OP even got defensive was because you guys were so hostile to begin with.