All my posts went 404 suddenly!

The answer, was in my .htaccess file don’t let any one change it.

<IfModule mod_rewrite.c>
RewriteEngine On
# If subdomain www exists, remove it first
RewriteCond %{HTTP_HOST} ^www\.([^\.]+\.[^\.]+)$ [NC]
RewriteRule ^(.*)$ https://%1/$1 [R=301,L]
# If requested resource does not exist as a file
RewriteCond %{REQUEST_FILENAME} !-f
# and does not end with a period followed by a filetype
RewriteCond %{REQUEST_URI} !..+$
# and does not end with a slash
RewriteCond %{REQUEST_URI} !/$
# then add a trailing slash and redirect
RewriteRule (.*) $1/ [R=301,L]
</IfModule>
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

Since some days, the photoblog of a friend is a catastrophy; 95% of his photos are not visible any more (error 404). My friend is a photopgrapher, no programmer. What can we do?

HELP!? Same happened to me – just noticed it today! Unfortunately Joseph’s code is greek to me. Had the .htaccess file been changed? Why/How? And what exactly does this solution code do? https://www.rocklandgreenmap.org