Recommended resolution for images in job posting so that it takes complete width of page

Summary:

Which is the recommended resolution for images in job posting, so that the picture takes the complete width of the job posting page, without any margins left?

Content (required):

I found some documentation on Oracle where they recommend a resolution of 2000 x 1125 pixels (ratio 16:9). But when trying with this resolution, I still see margins visible (see attachment).

We are using the "Minimal" template for our career site, for which the following is stated: "The other template, Minimal, allows for a width/height ratio which allows the media to be resized and avoid dead space." (source: https://support.oracle.com/cloud/faces/DocumentDisplay?_afrLoop=443904349571122&_afrWindowMode=0&id=2642043.1&_adf.ctrl-state=4ks49skkp_247