I have a story map which I'm authoring point by point in AGOL. The images I'm adding to the story map are great but when I view the story map either on my computer or on a device the images don't fill the available space in the 'image' section of the page. I'm ending up with grey wasted space around the image as the page tries to preserve the aspect ratio of the photo. I could change the pixel height and width to accommodate but that won't work particluarly well as the map will be loaded on different devices, etc. Is there a way I can force the image (and subtitle text/description) to 'fill' the available space in the image area?