A few moderately basic graphics questions...

I’m using very basic paint, drawImage type commands in my games and I have some (probably) simple graphics questions.

Resizing: at the moment my games play at 800x600 resolutions (I like the photo realism!) and I use display mode to alter the users screen to this resolution so they can play full screen. This works OK’ish on most folks screens but on others it doesn’t work at all or just shows a black screen. I know images can be resized so is it possible to resize the whole screen to fit the users current resolution? can it be done easily? and is it moderately efficient?

Darken: Is it possible to darken a whole screen and then slowly un-darken it? I tried painting a black rect over the whole image and slowly making the image transparent but this wasn’t very pretty or gradual.

Mist: I’m after a similar effect to the above in a different game but this game is set on an ice planet with falling snow and I wanted the “mist” to clear to show the game. Any ideas?

Image: I was quite happy with the look of the game above with the snow but a few people pointed out that the images I’m using are at odds with the game. I have bubbles floating around in the mist and snow above ice caps etc and some bubbles contain bombs that, when you shoot the bubble, the bomb will drop down onto the surface and restrict your movement. These bombs look like the round cartoon bombs with a lit fuse that sparkles away. They said that the old fashioned image of the bomb looked at odds with the space game - I think they’re right but I’m at a loss as what to use instead. Any thoughts?