diff --git a/classes/base_connector.php b/classes/base_connector.php
index 37d0547..c91f151 100644
--- a/classes/base_connector.php
+++ b/classes/base_connector.php
@@ -242,4 +242,15 @@ protected function get_headers(): array {
                 'Content-Type' => 'application/json;charset=utf-8',
         ];
     }
+
+    /**
+     * Returns the allowed mimetypes.
+     *
+     * This can be overwritten in connector classes that are capable of files being submitted.
+     *
+     * @return array an array of allowed mimetypes
+     */
+    public function allowed_mimetypes(): array {
+        return [];
+    }
 }
diff --git a/purposes/itt/classes/purpose.php b/purposes/itt/classes/purpose.php
index 5f08ba2..79951c4 100644
--- a/purposes/itt/classes/purpose.php
+++ b/purposes/itt/classes/purpose.php
@@ -17,6 +17,7 @@
 namespace aipurpose_itt;
 
 use coding_exception;
+use local_ai_manager\base_connector;
 use local_ai_manager\base_purpose;
 use local_ai_manager\local\connector_factory;
 use local_ai_manager\local\userinfo;
@@ -43,6 +44,23 @@ public function get_additional_purpose_options(): array {
             return [];
         }
 
-        return ['image' => PARAM_RAW];
+        return ['image' => PARAM_RAW, 'allowedmimetypes' => $this->get_allowed_mimetypes()];
+    }
+
+    /**
+     * Returns an array of allowed mimetypes for files being submitted.
+     *
+     * @return array array of allowed mimetypes, for example ['image/jpg', 'image/png']
+     * @throws coding_exception if the connector does not declare any allowed mimetypes
+     */
+    public function get_allowed_mimetypes(): array {
+        global $USER;
+        $userinfo = new userinfo($USER->id);
+        $factory = \core\di::get(connector_factory::class);
+        $connector = $factory->get_connector_by_purpose($this->get_plugin_name(), $userinfo->get_role());
+        if (!method_exists($connector, 'allowed_mimetypes') || empty($connector->allowed_mimetypes())) {
+            throw new coding_exception('Connector does not declare allowed mimetypes. Cannot be used for image to text');
+        }
+        return $connector->allowed_mimetypes();
     }
 }
diff --git a/tools/chatgpt/classes/connector.php b/tools/chatgpt/classes/connector.php
index c2d2144..bededcc 100644
--- a/tools/chatgpt/classes/connector.php
+++ b/tools/chatgpt/classes/connector.php
@@ -143,4 +143,9 @@ protected function get_headers(): array {
         }
         return $headers;
     }
+
+    #[\Override]
+    public function allowed_mimetypes(): array {
+        return ['image/png', 'image/jpeg', 'image/webp', 'image/gif'];
+    }
 }
diff --git a/tools/gemini/classes/connector.php b/tools/gemini/classes/connector.php
index f098641..29e2241 100644
--- a/tools/gemini/classes/connector.php
+++ b/tools/gemini/classes/connector.php
@@ -111,7 +111,7 @@ public function get_prompt_data(string $prompttext, array $requestoptions): arra
                             [
                                     'inline_data' => [
                                             'mime_type' => mime_content_type($requestoptions['image']),
-                                        // Gemini API expects the plain base64 encoded string, without the leading data url meta data.
+                                        // Gemini API expects the plain base64 encoded string, without the leading data url metadata.
                                             'data' => explode(',', $requestoptions['image'])[1],
                                     ]
                             ],
@@ -145,4 +145,11 @@ protected function get_headers(): array {
         }
         return $headers;
     }
+
+    #[\Override]
+    public function allowed_mimetypes(): array {
+        // We use the inline_data for sending data to the API, so we basically support every format.
+        // However, we restrict it to some basics.
+        return ['image/png', 'image/jpeg', 'image/webp', 'image/heic', 'image/heiff', 'application/pdf'];
+    }
 }
diff --git a/tools/ollama/classes/connector.php b/tools/ollama/classes/connector.php
index e8243f9..6239db6 100644
--- a/tools/ollama/classes/connector.php
+++ b/tools/ollama/classes/connector.php
@@ -107,4 +107,9 @@ public function get_prompt_data(string $prompttext, array $requestoptions): arra
         ];
         return $data;
     }
+
+    #[\Override]
+    public function allowed_mimetypes(): array {
+        return ['image/png', 'image/jpg'];
+    }
 }