This isn’t really much of a question, as much as a contribution to the community.
I spent quite sometime troubleshooting broken images and files on one of my clients websites. The files were on the server. The paths were 100% correct. The permissions were on par with what the platform requires and what any particular plug-in requires.
Yet, you still cannot get the images to appear or even open them up with a direct link to them in the browser.
I found that 9 times out of 10, you probably have a rogue .htaccess file in that directory causing the block. Even if you open the htaccess file and it has no erroneous information in it that would cause the issue, my suggestion would be to rename it to htaccess.txt and retest.
Hope this helps the next guy/gal!