diff --git a/cache/handle_404.php b/cache/handle_404.php
index 53e384c..0181921 100644
--- a/cache/handle_404.php
+++ b/cache/handle_404.php
@@ -8,6 +8,8 @@
 
 require_once __DIR__ . "/../required.php";
 
+header("Content-Type: text/plain;utf-8");
+
 $urlparts = explode("/", $_GET['file']);
 $fileparts = explode(".", end($urlparts));
 
@@ -21,12 +23,23 @@ if (!preg_match("/^[A-Za-z0-9\-!_]+$/", $fileparts[0])) {
     die("Encoded image URL invalid, refusing to parse.");
 }
 
-$url = Base64::decode($fileparts[0]);
+if (strpos($fileparts[0], "SHA1_") === 0) {
+    $hash = str_replace("SHA1_", "", $fileparts[0]);
+    if ($database->has("imagecache", ["hash" => $hash])) {
+        $url = $database->get("imagecache", 'url', ["hash" => $hash]);
+        echo $url;
+    } else {
+        http_response_code(404);
+        die("Not found.");
+    }
+} else {
+    $url = Base64::decode($fileparts[0]);
+}
 
 if (!filter_var($url, FILTER_VALIDATE_URL)) {
     http_response_code(403);
     die("Invalid URL.");
 }
 
-//header("Content-Type: image/jpeg");
-echo Thumbnail::addThumbnailToCache($url, (int) $fileparts[1]);
\ No newline at end of file
+header("Content-Type: image/jpeg");
+echo Thumbnail::addThumbnailToCache($url, (int) $fileparts[1]);
diff --git a/database.mwb b/database.mwb
index 26402ce..572f41e 100644
Binary files a/database.mwb and b/database.mwb differ
diff --git a/lib/Thumbnail.lib.php b/lib/Thumbnail.lib.php
index 12bb2a6..3eb5084 100644
--- a/lib/Thumbnail.lib.php
+++ b/lib/Thumbnail.lib.php
@@ -41,22 +41,44 @@ class Thumbnail {
     }
 
     /**
-     * Make a thumbnail, save it to the disk cache, and return a url relative to
-     * the app root.
+     * Return a thumbnail URL relative to the app root for the given image URL.
      * @param string $url
      * @param int $width
      * @param int,bool $height
      * @return string
      */
     static function getThumbnailCacheURL(string $url, int $width = 150, $height = true): string {
+        global $database;
         $encodedfilename = Base64::encode($url);
+        if (strlen("$encodedfilename.$width.jpg") > 250) {
+            // We're too long for common filesystems
+            $encodedfilename = "SHA1_" . sha1($url);
+            if (!$database->has("imagecache", ["url" => $url])) {
+                $database->insert("imagecache", ["url" => $url, "hash" => $encodedfilename, "created" => date("Y-m-d H:i:s")]);
+            }
+        }
         $path = "cache/thumb/$encodedfilename.$width.jpg";
 
         return $path;
     }
 
+    /**
+     * Generate a thumbnail and save it to the cache
+     * @param string $url
+     * @param int $width
+     * @param type $height
+     * @return type
+     */
     static function addThumbnailToCache(string $url, int $width = 150, $height = true) {
+        global $database;
         $encodedfilename = Base64::encode($url);
+        if (strlen("$encodedfilename.$width.jpg") > 250) {
+            // We're too long for common filesystems
+            $encodedfilename = "SHA1_" . sha1($url);
+            if (!$database->has("imagecache", ["url" => $url])) {
+                $database->insert("imagecache", ["url" => $url, "hash" => $encodedfilename, "created" => date("Y-m-d H:i:s")]);
+            }
+        }
         $path = "cache/thumb/$encodedfilename.$width.jpg";
         $image = self::getThumbnailFromUrl($url, $width, $height);
         file_put_contents(__DIR__ . "/../$path", $image);