some browsers do not have pixelDepth, so use empty string instead of undefined
some browsers do not have pixelDepth, so use empty string instead of undefined

lognormal/boomerang,sdgdsffdsfff/boomerang,FredXue/boomerang,levexis/boomerang,sdgdsffdsfff/boomerang,levexis/boomerang,FredXue/boomerang,lognormal/boomerang