Left to right is the strike ladder. The near edge is today; each row further back is a step closer to expiry. Height is how much dealer gamma sits there.
Dealers sold those options, so they must hedge. Where the hill is tall they buy every dip and sell every pop at that strike — price gets held. Where it is flat, nothing holds price, so it can travel. Red is the opposite: dealers there sell into falls and buy into rallies, which makes moves run further.
Strikes now / at expiry is how many strikes are really sharing the gamma. Fourteen means wide open. Two means one strike owns price.