A sound suppressor simply reduces the SOUND of gunfire by dispersing the gas from the end of the barrel in a different way. The gas and light from the explosion of the powder is still present. A "silenced" gun will still have muzzle flash, or light and flame.

so why in armed assault and arma 2 there was no any light and flame? it's a bug

THey have done a better job making it realistic.
Here is a video of an FN suppressed firing at night. It has the muzzle flash, though less pronounced as firing in the dark without a suppressor.
http://www.youtube.com/watch?v=bdPi0ggpvnw

thanks but there was very different with flame and light of a silenced and unsilenced weapon

http://answers.yahoo.com/question/index?qid=20120326203711AAxdkhb

Its one thing to have flame at the end, but what we have now is way way too much light.

http://www.orl-llc.com/nfa-pics/SRT-M16/6-02-2007/testing-6-2-07-c-950.jpg
Real flash at night.

Heres one with no suppressor.
http://i4.photobucket.com/albums/y141/nitesite9/R38S12_FBI_load.jpg

Can hardly light up the guys hand.

https://www.youtube.com/watch?v=mzhVEi3iOXA
Guy shooting at night, see how hes not lighting up like a flashlight is on him.

Heres one from A3.
http://cloud-2.steampowered.com/ugc/630792923196694128/74C4AFB3505F7F785105413C024923D6C304A1B3/

exactly Zacho! the flashlight is on shooter and it's not real

Would be nice to see this fixed.
Currently you can spot someone shooting suppressed weapon from very long range.

And by the way suppressor reduces the sound by slowing gas after it reaches muzzle break and lets it cool down (while it leaves the suppressor can itself). That means that flash is going to be significantly reduced as well.

Suppressed weapons do produce flame and light, just not that much light.

They promissed mutiple muzzle devices, so a flash hider would be cool, and yes too much light with silenced in my opinion

Duplicate of 768