@media screen and (min-width: 0px) {
  .itemGaleria {
    width: 48%;
    margin: 1%;
    float: left;
  }
}

@media screen and (min-width: 750px) {
  .itemGaleria {
    width: 48%;
    margin: 1%;
    float: left;
  }
}

@media screen and (min-width: 970px) {
  .itemGaleria {
    width: 48%;
    margin: 1%;
    float: left;
  }
}

@media screen and (min-width: 1170px) {
  .itemGaleria {
    width: 31%;
    margin: 1%;
    float: left;
  }
}