Previewing Hi Res Pictures is Blurry?

[sukanas]

i noticed that some of my pics are blurry/unfocused when i view them in preview or set them as wallpaper.. the picture itself is focused. i can tell because when i zoom in, it actually get clearer before i zoom in too much and make it get blurry..

anyone know why this happens?
i tried using that same image on my friends mac and in his preview it, it happens on his too

 

[toxic]

are they blurry when viewed at actual size (in Preview)? it could just be a poor resizing algorithm, or something along those lines. how big are the images?

 

[neutrino23]

It may be a sampling issue. Does the subject contain fine details like grass or moss? Your screen has a limited number of pixels so it will skip over some pixels when viewed at less than full resolution. This can lead to odd effects. If you want to view an image permanently at a lower resolution try converting it to that resolution with Graphic Converter or similar. This will try to smooth out these effects. Preview is probably already trying to do that to some extent. Not sure how effective it is.