let me give you a little advice.
If you're going to scale up an image, and if you are going to give it a higher resolution, do it this way, Go to Image > Image Size, set that resolution to an even multiple of the original.
So here I have started with 72. So I am going to set it to 288, four times the 72, and I am going to choose a special method, Nearest Neighbor. Notice that it says preserve hard edges.
Remember Nearest Neighbor when you have screenshots because that's the way to go. When I click OK, look, it's nice and sharp, it has a nicer resolution.
What I do sometimes if I want to make sure that my editor isn't going to freak out, I'll go back to Image Size-- sometimes people freak out when they just see the 288-- I uncheck Resample Image, I change that Resolution to 300.
What that means is that it's not making new pixels, it's just making the existing pixels a little bit smaller. When I click OK, nice and sharp, and I haven't lost anything. That's your overall goal, you don't want to lose any information; you want to maintain detail.