project image: introduce new "stable" with fixed timestamp image
project image: introduce new "stable" with fixed timestamp image

tscholl2/smc,tscholl2/smc,DrXyzzy/smc,sagemathinc/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,DrXyzzy/smc