Is .htaccess borking up subfolders?

I have a brand new host and a brand new install of WordPress. I have also enabled multisite/domain support.
WordPress is installed in the root of my domain. https://www.cp-fc.com
I have a couple of different subdomains setup that point to the root folder as per the instructions on another thread. WordPress and the subdomains appear to be working properly.

However: I have a php script that runs in another subfolder not related to WordPress at all. /roster When In invoke this script, none of the png images appear. File permissions are 755.

Also: I have another completely different domain name that points to a subdirectory /drake. I have a simple html file that displays one simple image. If that image is a png, it will not show up. If that image is a jpg it does just fine.

If I type the full address of a png image I get the following error. The image at “https://www.cp-fc.com/drake/fisher.png” cannot be displayed because it contains errors.
OR
The image at “https://www.drakeblackwell.com/fisher.png” cannot be displayed because it contains errors.

When I look at the source of the error, the error itself IS an image.

If I use a jpg however, it works fine.

I have NO .htaccess files in either /roster or /drake folders and my root .htaccess file is as follows:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^({_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule ^({_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

Has WordPress taken over all directories of my web folder? If so, is there a way to fix this, or should I blow out wp all together and re-install it under a sub folder such as /wp?