Downloading jpegs prob

I Have just bought a new digital camera,a samsung WB 1000 i am using a sdhc card 4GB class6.
The problem is the pictures look great on the camera,but when i download them to my computer they look out of focus not good at all,this also happens with my mobile phone camera which is a sony Erickson with 3.2 megapixel.
My camera is 12 megapixel, i have tried reducing the pixels but to no avail.
My computer is windows xp prof.
does anyone else have this problem, i have also tried a sdhc card reader but it is just the same.
So does anyone have any ideas why this should happen.
Thanks.