I installed BG, but as I start the game I noticed that game's resolution is 640x480!? why??? can I play this game 800-600 like BG2?

Am affraid that you're stuck with 640 Zoltan :( There's no way to change it....

While the 800x600 res does give you slightly smoother textures it also shrinks down the size of the animations. Is that really better? Try BG1 in 32 color deoth, btw.

I've always preferred an 800 x 600 screen resolution. Of course, it all depends on the size of your monitor (mine is 17") so having the graphics at 640 x 480 really makes it look pixellated and "grainy". I suppose on a 15" monitor it doesn't look too bad.

Yeah, mine is 17" inch (Dell P780) as well. I don't find BG1 all that much grainier than BG2. The difference in textures isn't that great to me but the character animations are to my eye noticeably smaller in BG2. That bothered me much more than the slightly grainier appearance.

I play on a 19' Monitor and don't find the graphic of BG1 that much worse, too.