Very much so. I-PNG yi-DEFLATE engalahlekiyo enesiqhagamshelanisi esipheleleyo se-8-bit alfa kunye nobunzulu obukhethwayo be-16-bit, ngoko ke ayizukuhlanganiswa kwi-re-save kodwa ifumana uninzi kwizinto eziqulethe imifanekiso. That determines both the headroom available and whether the saving costs you anything in fidelity.
Yes — akukho mqolo womgangatho ophosakeleyo — i-PNG ijikeleza-ihamba ngokuchanekileyo, ngoko into ekuphela kwayo eyenza utshintsho ibiza ubungakanani befayili. It is worth knowing before you overwrite an original you might need again.
Yintoni impazamo eqhelekileyo xa uxinzelela PNG images?