You can try moving the padding to target a different element however you can also try pulling the image out of the container with some negative margins e.g.
.charity-header {
margin: -3rem -3rem 0 -3rem;
}
Typically negative margins can be considered a bad practice however for pulling images out of containers this trick is useful in my opinion.
It looks like you have 3rem of padding around the .site element which is causing your banner images to have some white space e.g. this page: https://rethink.van.cp.academy.red/charity/coalition-for-rainforest-nations-cfrn/
You can try moving the padding to target a different element however you can also try pulling the image out of the container with some negative margins e.g.
Typically negative margins can be considered a bad practice however for pulling images out of containers this trick is useful in my opinion.