Hi,
I have been designing a site based on my laptop. The website has html background colours with light greys. However when I view the website on screens the light greys are almost invisible and appear white on the screen.
Should I use an image as a background to ensure the website appears the same colour on different screens?
Using a similar shade/colour image in place of those greys possibly won’t make much difference; it is the limitation of the screen and graphics settings, etc. The colours here [SPF] look good on my large Iiyama ProLite, LED IPS monitor for my desktop but if I were to use my Netbook they would look pretty dark; less definable, and a lot less distinguishable. Nowhere near as pleasing to the eye, and images would look nowhere as vibrant either.
As Robert said using images would make no difference.
On my PC with new Samsung monitor and optimal settings I can still barely see #f2f2f2 while on the Mac its as bright as a (bright) button. You just have to design with this in mind and user more contrast if its an issue.
One of my clients complained that when he turned his flat screen monitor at a large angle away from him the colours looked different and could I make sure it doesn’t happen again!
I came up with a solution but it involved nailing the client and the monitor into a fixed position which wasn’t acceptable 
Different screens often produce this problem.
Different brightness and contrast settings make it harder still.
I remember the day I opened one of my sites in a browser which was open on my spare old screen - I thought the site had been hacked as the colours were all wrong! As I dragged the browser window across onto my main laptop screen, getting ready to log in and check things, the colours returned to normal. But on this new laptop, that doesn’t happen to any noticeable extent.
Yea. I had the same problem and result was the same.