You just have to reset the values you don't want to their defaults. No need to get into a mess by using !important
.
#zoomTarget .slikezamenjanje img {
max-height: auto;
padding-right: 0px;
}
I think the key datum you are missing is that CSS comes with default values. If you want to override a value, set it back to its default, which you can look up.
For example, all CSS height
and width
attributes default to auto
.