Today I’ve spend most of the day trying to make a banner for the CGC profile.
it says 1920 x 1080 pixels recommended, so made one. After finished uploaded to my profile.
Checked the profile and it has some kind of zoom function in it.
The layout of the 1920 x 1080 pixels recommended file is almost cut in half.
So tried to make one with less height, uploaded the new version, same issue.
So uploaded small version 600 x 314 px and yes same issue.
The cropper that you are referring to ensures that your image will keep the size ratio of the container. The cropper allows you to zoom in and out using the mouse scroller or the orange scroller bellow the preview.
In the case of the banner 1920 x 1080 it means that an image of equal dimensions will not be cropped unless you zoom in.
For backgrounds it is a little bit different. The cropper will pop up but the image will not be cut without zoom even if the selected image is higher than the container. In that case you can adjust the image using the background-size field located in the sidebar of the editor.