diff --git a/src/controller/image/generation.rs b/src/controller/image/generation.rs
index 823593b..9bfb672 100644
--- a/src/controller/image/generation.rs
+++ b/src/controller/image/generation.rs
@@ -10,6 +10,7 @@ use crate::conversation::create_llm_conversation_for_matrix_thread;
 use crate::conversation::matrix::MatrixMessageProcessingParams;
 use crate::strings;
 use crate::{entity::MessageContext, Bot};
+use crate::controller::utils::mime::get_file_extension;
 
 // We may make this configurable (per room, etc.) in the future, but for now it's hardcoded.
 const STICKER_SIZE: &str = "256x256";
@@ -81,7 +82,7 @@ pub async fn handle_image(
             .await;
     }
 
-    let attachment_body_text = format!("Generated image based on: {}", actual_prompt);
+    let attachment_body_text = format!("generated-image.{}", get_file_extension(&response.mime_type));
 
     let mut event_content = matrix_link
         .media()
@@ -157,7 +158,7 @@ pub async fn handle_sticker(
         .instrument(span)
         .await?;
 
-    let attachment_body_text = format!("Generated sticker image based on: {}", original_prompt);
+    let attachment_body_text = format!("generated-sticker.{}", get_file_extension(&response.mime_type));
 
     let mut event_content = matrix_link
         .media()
diff --git a/src/controller/utils/mime.rs b/src/controller/utils/mime.rs
new file mode 100644
index 0000000..8c9a8e7
--- /dev/null
+++ b/src/controller/utils/mime.rs
@@ -0,0 +1,16 @@
+use mxlink::mime;
+
+pub fn get_file_extension(mime_type: &mime::Mime) -> String {
+    match (mime_type.type_(), mime_type.subtype()) {
+        (mime::AUDIO, mime::BASIC) => "au",
+        (mime::AUDIO, mime::MPEG) => "mp3",
+        (mime::AUDIO, mime::MP4) => "m4a",
+        (mime::AUDIO, mime::OGG) => "ogg",
+        (mime::IMAGE, mime::BMP) => "bmp",
+        (mime::IMAGE, mime::GIF) => "gif",
+        (mime::IMAGE, mime::JPEG) => "jpg",
+        (mime::IMAGE, mime::PNG) => "png",
+        (mime::IMAGE, mime::SVG) => "svg",
+        _ => "bin",
+    }.to_string()
+}
diff --git a/src/controller/utils/mod.rs b/src/controller/utils/mod.rs
index 9f493c1..f7b9a25 100644
--- a/src/controller/utils/mod.rs
+++ b/src/controller/utils/mod.rs
@@ -7,6 +7,7 @@ use crate::{
 
 pub mod agent;
 pub mod text_to_speech;
+pub(super) mod mime;
 
 pub async fn get_text_body_or_complain<'a>(
     bot: &Bot,
diff --git a/src/controller/utils/text_to_speech.rs b/src/controller/utils/text_to_speech.rs
index e55f81e..0178b66 100644
--- a/src/controller/utils/text_to_speech.rs
+++ b/src/controller/utils/text_to_speech.rs
@@ -3,6 +3,7 @@ use mxlink::{MatrixLink, MessageResponseType};
 
 use tracing::Instrument;
 
+use crate::controller::utils::mime::get_file_extension;
 use crate::{
     agent::{provider::TextToSpeechParams, AgentInstance, AgentPurpose, ControllerTrait},
     entity::MessageContext,
@@ -117,7 +118,7 @@ async fn do_generate_and_send_tts_for_message(
         }
     };
 
-    let attachment_body_text = strings::text_to_speech::alternate_body_text();
+    let attachment_body_text = format!("generated-speech.{}", get_file_extension(&text_to_speech_result.mime_type));
 
     let event_content = matrix_link
         .media()
diff --git a/src/strings/text_to_speech.rs b/src/strings/text_to_speech.rs
index e9f9ee7..19e9f2f 100644
--- a/src/strings/text_to_speech.rs
+++ b/src/strings/text_to_speech.rs
@@ -1,7 +1,3 @@
-pub fn alternate_body_text() -> String {
-    "Generated speech from text".to_owned()
-}
-
 pub fn redaction_reason_done() -> &'static str {
     "Done with speech-to-text"
 }