Yes, we can expect PLAAF to hold on to J-8 II for quite some time. For one thing, they are not terribly old, being built between 1996 and 2006 (not counting the recce version JZ-8F). For another, there are not too many of them, only six fighter regiments in PLAAF (6x28 = 168) and 1½ in PLANAF (26 + 12 = 38.
The two planes in the picture may actually be some of the first to go: 20630 and 20636 are pre-2005 pictures of 12 Div 35 Regt Gaomi J-8B’s, which reportedly have not been upgraded to J-8BH. They may thus be some of the first to be replaced by J-20.