I'm having Itunes problems...?

i added songs from my Now CD's onto itunes and i changed the albums to the albums they originated from (like i got mmmbop by hanson from Now 1 and then changed the album from greatest hit vol. 1 or whatever to middle of nowhere since that is where the song is in hanson CD's) and then i clicked find album artwork. it won't find any of the artwork for any of the music i got from the Now CD's. well it finds artwork but it's not the right art work. it's this weird picture and it's the same for all the Now CD songs. how do i get it to find the artwork for the info (album and artist) i put in?I'm having Itunes problems...?right click on the songs, click get info, find the tab that says %26quot;artwork%26quot;, then go to google, find a picture of it, copy and paste.