Can't preview custom template

When I go to "tools" then "template selection", and try to preview my custom template, I get:
"You don't have permission to access /zen/includes/templates/custom/images/ on this server."

I checked my permissions and they seemed okay--755

It says the template is installed & says the description. I can preview the classic contemporary green one fine.

I discovered this while trying to change the logo on the welcome e-mail. I followed this: https://www.zen-cart.com/tutorials/index.php?article=125
and did everything it said, but the zen cart logo shows up instead of mine.

Do you have this file:
/zen/includes/templates/custom/template_info.php

Make sure the file has correct permissions and has been editted to reflect your custom Template.

Directory permissions on a Linux Server are 755 whilst file permissions are 644. You should check that permissions are according to what they should be.

It says the template is installed & says the description. I can preview the classic contemporary green one fine.
Many cntributed templates do not include the thumbnail preview image so are not previewable...just enable it to see it on your site