Best way to render/animate 2d using openGL?
So I'm making a game in C++. And I'm at a fork in the road.

I am now planning how I am going to handle animation and optimize rendering. I'm rendering using immediate mode which I was told was very slow. I go looking for alternatives and then there's a bunch of different ways, and it differs depending on how you handle the animations, so I thought I'd just ask what would be a good optimal way to do both.

For animations, I thought about using sequences of images stored in memory, but only testing with a 50 image sequence, memory jumped to like 200 mb, when it was 30 before. (There's no leak, it stays at 200, but if I have large levels, it looks like I'll be running out of memory). Would sprite sheets help in this case?

I was told the reason atlases or sprite sheets were used was because binding different textures was an expensive operation, so the only way this would work is by putting in all the texture I will use for level 1 for example in one huge texture so I'm only binding once. Is this possible dynamically? 

Would using one gigantic PNG be better memory-wise than loading 50 PNG's?

**Any help with either optimizing rendering or some information about the drawbacks of these animation techniques would be really appreciated!**

Thanks!
Best way to render/animate 2d using openGL?
===

So I'm making a game in C++. And I'm at a fork in the road.

I am now planning how I am going to handle animation and optimize rendering. I'm rendering using immediate mode which I was told was very slow. I go looking for alternatives and then there's a bunch of different ways, and it differs depending on how you handle the animations, so I thought I'd just ask what would be a good optimal way to do both.

For animations, I thought about using sequences of images stored in memory, but only testing with a 50 image sequence, memory jumped to like 200 mb, when it was 30 before. (There's no leak, it stays at 200, but if I have large levels, it looks like I'll be running out of memory). Would sprite sheets help in this case?

I was told the reason atlases or sprite sheets were used was because binding different textures was an expensive operation, so the only way this would work is by putting in all the texture I will use for level 1 for example in one huge texture so I'm only binding once. Is this possible dynamically? 

Would using one gigantic PNG be better memory-wise than loading 50 PNG's?

**Any help with either optimizing rendering or some information about the drawbacks of these animation techniques would be really appreciated!**

Thanks!