How do I resize the whole game from HD to SD?

Hello, I'm making a game and I already reach 600mb of memory used for only 200 events, how is it possible?

Approximative download size: 62mb.

I paid attention on the events such as "every tick" or loops, I desabled all "collision" and all my sprites couldn't be lighter. Also all sprite going outsite the layout are destroyed, I don't use any effect and physics is very low (like 2% used). When I launch the game it only use a maximum of 12% UC (I have a 2,9Ghertz), it never lag, so where do the 600 come from?

The game works on a HD layout, so basically 4x "bigger" than SD (if it works like photography). I have the feeling that's the problem

What I don't understand is how it could need more memory if the images size are very low (max 80kb), I suppose a big picture of white take more time to load than a smaller one of the same weight? I didn't know that, is it correct?

Do you think I can reach 150mo if I put my layout to SD? How to do that? Is it possible? Do I forget something important?

Also when I render the game with node-webkit it doesn't take 600mb but 1200mb, the application seems to start 2 times, but both are working because when I cancel one of them the game crash. Is it normal or I must re-instal?

Thank you for you help please

It's likely you have too many large images, by dimensions instead of size on disk. Images are uncompressed when they're loaded into memory, so you can have a 1024x1024 image that's 10KB as a PNG, but when uncompressed and loaded into memory, that image will be 4MB.