diff --git a/ext/eokm/info.php b/ext/eokm/info.php
new file mode 100644
index 00000000..23a5fb4c
--- /dev/null
+++ b/ext/eokm/info.php
@@ -0,0 +1,13 @@
+<?php declare(strict_types=1);
+
+class EokmInfo extends ExtensionInfo
+{
+    public const KEY = "eokm";
+
+    public $key = self::KEY;
+    public $name = "EOKM Filter";
+    public $url = self::SHIMMIE_URL;
+    public $authors = self::SHISH_AUTHOR;
+    public $license = self::LICENSE_GPLV2;
+    public $description = "Check uploads against the EOKM blocklist";
+}
diff --git a/ext/eokm/main.php b/ext/eokm/main.php
new file mode 100644
index 00000000..ea704c68
--- /dev/null
+++ b/ext/eokm/main.php
@@ -0,0 +1,52 @@
+<?php declare(strict_types=1);
+
+class Eokm extends Extension
+{
+    public function get_priority(): int
+    {
+        return 40;
+    } // early, to veto ImageUploadEvent
+
+    public function onImageAddition(ImageAdditionEvent $event)
+    {
+        global $config;
+        $username = $config->get_string("eokm_username");
+        $password = $config->get_string("eokm_password");
+
+        if($username && $password) {
+            $ch = curl_init("https://api.eokmhashdb.nl/v1/check/md5");
+            // curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/xml', $additionalHeaders));
+            curl_setopt($ch, CURLOPT_HEADER, 1);
+            curl_setopt($ch, CURLOPT_USERPWD, $username . ":" . $password);
+            curl_setopt($ch, CURLOPT_TIMEOUT, 30);
+            curl_setopt($ch, CURLOPT_POST, 1);
+            curl_setopt($ch, CURLOPT_POSTFIELDS, $event->image->hash);
+            curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
+            $return = curl_exec($ch);
+            curl_close($ch);
+
+            if($return == "false") {
+                // all ok
+            }
+            elseif($return == "true") {
+                log_warning("eokm", "User tried to upload banned image {$event->image->hash}");
+                throw new UploadException("Image banned");
+            }
+            else {
+                log_warning("eokm", "Unexpected return from EOKM: $return");
+            }
+        }
+    }
+
+    public function onSetupBuilding(SetupBuildingEvent $event)
+    {
+        $sb = new SetupBlock("EOKM Filter");
+
+        $sb->start_table();
+        $sb->add_text_option("eokm_username", "Username", true);
+        $sb->add_text_option("eokm_password", "Password", true);
+        $sb->end_table();
+
+        $event->panel->add_block($sb);
+    }
+}
diff --git a/ext/eokm/test.php b/ext/eokm/test.php
new file mode 100644
index 00000000..fda6adaa
--- /dev/null
+++ b/ext/eokm/test.php
@@ -0,0 +1,27 @@
+<?php declare(strict_types=1);
+
+class EokmTest extends ShimmiePHPUnitTestCase
+{
+    public function testPass()
+    {
+        // no EOKM login details set, so be a no-op
+        $this->log_in_as_user();
+        $this->post_image("tests/pbx_screenshot.jpg", "pbx computer screenshot");
+        $this->assert_no_text("Image too large");
+        $this->assert_no_text("Image too small");
+        $this->assert_no_text("ratio");
+    }
+
+    /*
+    public function testFail()
+    {
+        $this->log_in_as_user();
+        try {
+            $this->post_image("tests/pbx_screenshot.jpg", "pbx computer screenshot");
+            $this->assertTrue(false, "Invalid-size image was allowed");
+        } catch (UploadException $e) {
+            $this->assertEquals("Image too small", $e->getMessage());
+        }
+    }
+    */
+}