Lively computer graphics may be (8)
I believe the answer is:
animated
'lively' is the definition.
(similar in meaning)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for animated that I've seen before include "Interesting and lively - as a cartoon film is" , "in cartoon form" , "'Lively, quick (8)'" , "Full of excitement, lively" , "Enlivened (like a cartoon film)" .)