I don't exactly know what you are asking about. You can set the number of images album.php should show in the admin options.
"fit on screen (without need of scrolling)" is a very relative term, since not everyone has the same screen resolution or the same viewport size (browse window size).
thanks a lot for your kindness... and sorry for my funny question... i have thought to put 4 images(2 columns... and to make this i already have problems ) like collage and a method to recognize, at least, screen resolution for scaling automatically... and sorry my eglish is too poor...
papero from italy
It is absolutly no problem to make a theme with 4 images in 2 columns, but scaling to fit the screen size I don't think makes sense. Better choose a size that fits the most common screen resolution today, which would be 1024x768px as the minimum.
But of course depending on our html/css abilities you can make that scale, too.
PS: No problem with your english.