I've just uploaded a 70kb .jpg file and the attachment just displays the file name. No image and no link. My max file size to display inline images is set to 500kb.

Test

Test above shows that it works on here.

Worked fine on my forum before I upgraded to 7.5b2 from 7.4.2

I've just checked my attachments directory. Path is correct and permissions.

I have attached the image file again and it has uploaded to the attachments directory.

I have uploaded a different image with a known good image to check that it wasn't a file error with the same outcome.

Another update: All posts with existing inline attachments are now only displaying the file name and not the image.

Example post from 2007.

Same issue here.
For thrills turned off the nofollow options in the cp and rebuilt content. Still no inline image or link to image.

Error log:

PHP Fatal error: Call to undefined function apache_request_headers() in /home/******/public_html/ubbthreads/scripts/download.inc.php on line 82

No errors on my side. Server or control panel.
Just does not work.

Okay I will try a test here also. Don't know what the inline setting is but in any case should at least have a link to the file here.

Okay it works here but not on my site with 7.5b2

Look for error_log in your ubb directory.