diff --git a/app/src/main/java/eu/faircode/email/ActivitySignature.java b/app/src/main/java/eu/faircode/email/ActivitySignature.java
index 8144ee7312..afa488a080 100644
--- a/app/src/main/java/eu/faircode/email/ActivitySignature.java
+++ b/app/src/main/java/eu/faircode/email/ActivitySignature.java
@@ -389,6 +389,21 @@ public class ActivitySignature extends ActivityBase {
                 ssb.setSpan(is, start + 1, start + 2, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
                 etText.setText(ssb);
                 etText.setSelection(start + 2);
+
+                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
+                boolean signature_images_hint = prefs.getBoolean("signature_images_hint", false);
+
+                if (!signature_images_hint)
+                    new AlertDialog.Builder(this)
+                            .setTitle(R.string.title_hint_important)
+                            .setMessage(R.string.title_edit_signature_image_hint)
+                            .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+                                @Override
+                                public void onClick(DialogInterface dialog, int which) {
+                                    prefs.edit().putBoolean("signature_images_hint", true).apply();
+                                }
+                            })
+                            .show();
             }
         } catch (SecurityException ex) {
             Snackbar sb = Snackbar.make(view, R.string.title_no_stream, Snackbar.LENGTH_INDEFINITE)
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
index 03ec8d8476..c25f28cb11 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
@@ -214,7 +214,8 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             "identities_asked", "identities_primary_hint",
             "raw_asked", "all_read_asked", "delete_asked",
             "cc_bcc", "inline_image_hint", "compose_reference", "send_dialog",
-            "setup_reminder", "setup_advanced"
+            "setup_reminder", "setup_advanced",
+            "signature_images_hint"
     };
 
     @Override
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 0467703526..20ae33cbb3 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1474,6 +1474,10 @@
     <string name="title_edit_signature_remark">Although Android cannot display all HTML, it will be sent as-is</string>
     <string name="title_edit_signature_text">Signature text</string>
     <string name="title_edit_signature_image">Insert image</string>
+    <string name="title_edit_signature_image_hint">
+        When sending a message, the image is copied into the message from the selected location.
+        So, don\'t delete the image file!
+    </string>
 
     <string name="title_answer_caption">Edit template</string>
     <string name="title_answer_reply">Reply template</string>