I am currently working on a simple 2D Tile-Based game where you control a circle (you) trying to shoot down other CPU circles with a different team.

Screenshot

The Lines are "Bullets".


As you can see, the Tiles are 16x16. No problems here.
But i thought of making an option for the user to have a 1x1 Terrain,
Just like in Worms-Based-Games. You can then import a custom made picture of your own map to the game, and the game will remove all black pixels and replace them with empty space.

The problems with 1x1 Terrains is:
It eats more than 500 000 kB of Memory. I use the following code to define all Tiles:
Code:
Dim Tile(-1 To 11549, -1 To 11549) As Long
It is also very slow to draw every pixel that fits in the screen.

Or maybe you don't need a tile system to work with terrains?
Someone please point me in the right direction

Thanks for all help given!