Removing staging from the link makes the image displayed, but after did a hard-refresh then the images were gone, this can be caching of the browser.
Global Assets has Read right for everyone doesn't mean it has expected rights for the expected Groups. The mentioned expected groups are IUSR & IIS_IUSRS, normally at my side its permissions (on the "appdata" folder) looks like: http://i.imgur.com/Qaad76N.png
Remember restarting the site or the IIS after changing the folder permissions.
If the server returns a 500 error you should turn on logging and check the log files to see if you can find a more detailed error message.
Thanks for the help, guys. I don't actually have access to the server on which this site was runnning, so I just asked the people that do to look at it.
They fixed the issue and now all images are present. It may have been something as dumb as the images missing from the blob folder.
I've taken over a new site so I'm new to EpiServer and I'm having an issue on a staging site where all of the static images on that site are no longer being displayed.
Here is a screenshot of all of the images in the 'Select Media' popup showing that all the images are not being displayed: http://i.imgur.com/9Cah3Mi.png
An example url for an image is: http://staging.mysite.com/globalassets/homepage-banner-images/img-marquee-all-products.png, which returns 'Page could not be loaded' and the server actually responds with a 500, which I would've expected a 404.
If I remove 'staging' from the above link, the image is displayed from the live site as expected. The images were present on Friday and when I did a hard-refresh (ctrl+f5) this morning on the same site all of the images were gone. I checked the access rights and the Global Assets item has read rights for everyone.
Any ideas what may be causing this? Any help is appreciated.