Graphic size standard?

That's quite a wide topic.

You have some options and it all depends on how do you want the graphics to look like:

1.

The graphics can be procedural (is that the right word?), in which case it will scale happily to any resolution automatically. It's like talking about vector and bitmap images in a picture editor - you can scale the vector one to any size you wish and it will still look nice, while with the bitmap one you have only a single size which looks perfect. In your case, you could easily model the spaceships as 3D objects (vertices, polygons etc.) and still draw them in 2D view. The game will be completely independent on resolution.

2.

If you have a sprite-based graphics (pre-drawn bitmap images) then you have two basic choices:

a) You always map the sprites 1:1 to screen pixels. Let's say the player's ship is 40x40 pixels. It will be that big on all resolutions, so in 800x600 it will take 5 % of the screen width, while on 1920x1200 it will be 2.08 %. The result is that you can see more of the world around you without scrolling. This was used mainly in old RTS and RPG games. Having a bigger monitor allowed you too see more of the world at once. Which can also be unfair for example in a multiplayer game, so I wouldn't recomend this approach much. Anyway - it depends only on the design of your game whether this is applicable and suitable or not.
b) Every sprite always occupies the same region relative to the screen size, so you must be resizing them. When it comes to resizing, I think you could use both of the methods you mentioned - either draw the images in a high resolution and scale them down when needed or make a set of images and use the closest bigger one. But - while preparing the set of images, you'll most probably be drawing a large one and then scaling it down in a picture editor. So, why just not let the game do it itself? ;) This is very close to the mipmapping term.


What you must keep in mind anyway though, are different aspect ratios. Some players use 4:3, other use 16:9 - the difference is quite huge. When I was talking about seeing more on the screen on larger monitors (2 a), you usually must do this anyway for wide monitors. You cannot stretch the sprites on one axis to fill a 16:9 screen the same way as a 4:3 screen when using the resizing option (2 b). A player with a widescreen monitor will see more in the horizontal direction that a player with a 4:3 screen. Unless you present him with black areas on the sides.



Oh and as a side note - here (http://store.steampowered.com/hwsurvey) is a survey of monitor resolutions used by a very large sample of players.

[Edited by - Tom KQT on January 7, 2011 3:26:47 AM]

The site transition got me sidetracked from GameDev.net for a bit, so I almost forgot about this post. Thanks Tom! This is very useful information, even if it might be a bit obvious for those besides myself. =]