Sad, sad, news. Situation hasn't changed, except I can chmod 777 & 666 the required directories now. I've managed to change the suphp.conf to allow all true and reinstalled UBB.threads according to the Installation Guide and the Image Verification image remains blank for Guests...

Display Settings: General > New Post/Reply Page Settings: GD2 & ImageMagick images are visible.

My Samsung phone browser and Internet Explorer loads a broken image, but I have to click the broken image to request a new one. Firefox and Chrome, blank.

Freshly installed test directory (/1).

Quote
UBB.threads System Requirements Test

System Requirements Not Met

The following system requirements were not met. Please contact your host for help.

The required PHP extension Iconv could not be found. Please ask your host to install this extension. Please see UBBWiki: iconv

Possible Problems

Possible problems have been detected, please see the individual messages below for more information.

It would seem that the PHP function "file_get_contents" does not allow remote content, please advise your host that you need the setting "allow_url_fopen" to be enabled; if it remains disabled you will be unable to use the Stop Forum Spam functionality. Please see UBBWiki: allow_url_fopen

Additional Information
File Get Contents: Does NOT Allow External URLs
GZip: GZip is supported on this system.
Maximum Execution Time: 60 Seconds
Maximum UBB.threads Version: v7.6.x (UBBWiki: "Server Requirements and Suggestions")
Maximum Upload File Size: 2M (see php.net for more information)
Memory Limit: 384M
MySQL: MySQL v5.0 or newer is required; please manually check that you meet this requirement.
PHP Interface: cgi-fcgi
PHP Version: v5.4.45
Reported Host: www.aliendisc.net
Reported OS: Linux
Reported Port: 443 (443 indicates SSL)
Post Max File Size: 8M (can affect the upload size, see php.net for more information)
Time: The current, unadjusted, server time is: Sunday, October 22nd, 2017 at 04:16 AM, UTC (+00:00)
ZLib: ZLib is supported on this system.

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[Linked Image from aliendisc.net]
[Linked Image from aliendisc.net]