The yellow sign reads: "This much shame, to hell with this life", signed in the upper left-hand corner of the banner, by The workers of Meh-Nakh and Far-Nakh weaving factories.
The child holds up a sign saying: "We have not been paid between 7 to 12 months. Signed by The Workers of Poosheeneh Baft Weaving company."
The protests pictured in posting #4 appear to be about worker unrest over not getting paid. While certainly understandable on their part, I don't get the impression that they are fomenting revolt against Khomeinism, or even the regime per se.
Am I missing something here? This reminds more of the tractor stunt ("Tractorcade") pulled during the Carter Administration rather than Tiananmen: