AVAST PRO V4.7 + MSN PICTURE DISPLAYER

Hi ! everyboy
Minimir the frenchie posting for the first time.
When MESSENGER add-on called “Picture Displayer”, is running, AVAST icon is turning anytime, scanning and scannin again !!!
My CPU works dramatically, never restling under 50 -60 %
Anybody has an opinion ??

If you disable avast, or IM and WebShield providers, will it help?
Any other security program that could interfere?
Which is your operational system and firewall?