The Browser can make a difference.
I use Chrome as my main browser and occasionally when I can't see an image I try in Edge and I see it. Also if you are viewing on a Smart phone, iPad or PC the Browser could behave differently. Plus any settings that might have been selected within the Browser.
(Chrome is stricter about blocking "mixed content" (loading HTTP images on an HTTPS page) for security reasons. If your hosted images are served over HTTP but your site is loaded over HTTPS, Chrome may block those images, while Edge may still display them depending on its security settings.)