malware – .htaccess to stop scripts with image extensions

I use a .htaccess file in my images directory to block scripts from running. I exclude .php .cgi and so on. But some malware are disguised by naming them with an image extension. I did not previously add various image extensions fearing it could prevent images from displaying on site pages. My question is three fold.

1> would adding image extensions prevent any malware with an image extension from being executed?

2> would adding extensions to the .htaccess impact the normal loading of an image as asset into content pages?

3> Could I place limit in the /root .htaccess file to prevent running anything with image extensions as a script to protect entire site from this kind of exploit without causing issues with proper display of images? (obviously not including any actual scripts that are required to run)

example:

<Files .htaccess>
order allow,deny
deny from all
</Files>

Options -Indexes
Options -ExecCGI
AddHandler cgi-script .php .php3 .php4 .phtml .pl .py .jsp .asp .htm .shtml .sh .cgi

## No directory listings
<IfModule autoindex>
  IndexIgnore *
</IfModule>

## Suppress mime type detection in browsers for unknown types
<IfModule mod_headers.c>
Header always set X-Content-Type-Options "nosniff"
</IfModule>