Unable to view Files as thumbnails when creating item within Directus

From directus created by philleepflorence : directus/directus#1935

Version Info

• Directus version and branch: 6.4.3
• PHP version: 7
• MySQL version: 5.7
• Web server: Apache
• OS name and version: CentOS 7

Expected Behavior

When selecting Choose Existing in Single or Multiple Files Interface, one would see thumbnails of files to select.

Actual Behavior

When selecting Choose Existing in Single or Multiple Files Interface, one sees rows of files, with no image preview.

Steps to Reproduce

1. Add a single or multiple file input to any table.
2. Create a new item and try to add image

Schema Dump, Logs, or Screenshots

Table: directus_tables

Table: directus_preferences

Table: directus_columns