Thanks @cyberdave! Read only link is here: https://preview.webflow.com/preview/leegriffithsphotography?preview=9394ca3adb706d535652ca8ad2f4f4dc
The link that's not displaying correctly is my main 'custom' domain: www.leegriffithsphotography.com. The image that should be displaying is:
I've tried hosting the image on somewhere like 'PhotoBucket' which didn't work, I've also tried Flickr too. I've finally resorted to using the link that's contained within the assets section of the designer, which also doesn't seem to work.