1. Within Control Panel > Permission Checks, the path permissions tool will check all files and directories to have the proper permissions.

2. Within Control Panel > Paths & Database, confirm that these paths are correct:
Absolute PATH to Path to Convert, Example: /usr/bin/convert
and
Absolute PATH to Path to Mogrify, Example: /usr/bin/mogrify

A real-time pseudo check to determine if your ImageMagic or GD are reachable is to visit the Control Panel > General > CAPTCHA Settings group and check if the images are being generated and displayed correctly. If they are not displayed, then your graphics libraries paths are incorrect or unreachable.

example:
[Linked Image]

3. Within Control Panel > Attachments > Image Processing, confirm that you have selected a functional graphics library to use for image processing
Attachments