diff --git a/toot/api.py b/toot/api.py
index 29811da..984ad37 100644
--- a/toot/api.py
+++ b/toot/api.py
@@ -1,11 +1,13 @@
+import mimetypes
+from os import path
 import re
 import uuid
 
-from typing import List
+from typing import BinaryIO, List, Optional
 from urllib.parse import urlparse, urlencode, quote
 
-from toot import http, CLIENT_NAME, CLIENT_WEBSITE
-from toot.exceptions import AuthenticationError
+from toot import App, User, http, CLIENT_NAME, CLIENT_WEBSITE
+from toot.exceptions import AuthenticationError, ConsoleError
 from toot.utils import drop_empty_values, str_bool, str_bool_nullable
 
 SCOPES = 'read write follow'
@@ -347,11 +349,40 @@ def anon_tag_timeline_generator(instance, hashtag, local=False, limit=20):
     return _anon_timeline_generator(instance, path, params)
 
 
-def upload_media(app, user, file, description=None):
-    return http.post(app, user, '/api/v2/media',
-        data={'description': description},
-        files={'file': file}
-    ).json()
+def upload_media(
+    app: App,
+    user: User,
+    media: BinaryIO,
+    description: Optional[str] = None,
+    thumbnail: Optional[BinaryIO] = None,
+):
+    data = drop_empty_values({"description": description})
+
+    # NB: Documentation says that "file" should provide a mime-type which we
+    # don't do currently, but it works.
+    files = drop_empty_values({
+        "file": media,
+        "thumbnail": _add_mime_type(thumbnail)
+    })
+
+    return http.post(app, user, "/api/v2/media", data=data, files=files).json()
+
+
+def _add_mime_type(file):
+    if file is None:
+        return None
+
+    # TODO: mimetypes uses the file extension to guess the mime type which is
+    # not always good enough (e.g. files without extension). python-magic could
+    # be used instead but it requires adding it as a dependency.
+    mime_type = mimetypes.guess_type(file.name)
+
+    if not mime_type:
+        raise ConsoleError(f"Unable guess mime type of '{file.name}'. "
+                           "Ensure the file has the desired extension.")
+
+    filename = path.basename(file.name)
+    return (filename, file, mime_type)
 
 
 def search(app, user, query, resolve=False, type=None):
diff --git a/toot/commands.py b/toot/commands.py
index 9941e23..1a887de 100644
--- a/toot/commands.py
+++ b/toot/commands.py
@@ -142,14 +142,16 @@ def _get_scheduled_at(scheduled_at, scheduled_in):
 
 
 def _upload_media(app, user, args):
-    # Match media to corresponding description and upload
+    # Match media to corresponding description and thumbnail
     media = args.media or []
     descriptions = args.description or []
+    thumbnails = args.thumbnail or []
     uploaded_media = []
 
     for idx, file in enumerate(media):
         description = descriptions[idx].strip() if idx < len(descriptions) else None
-        result = _do_upload(app, user, file, description)
+        thumbnail = thumbnails[idx] if idx < len(thumbnails) else None
+        result = _do_upload(app, user, file, description, thumbnail)
         uploaded_media.append(result)
 
     return [m["id"] for m in uploaded_media]
@@ -297,7 +299,7 @@ def activate(app, user, args):
 
 
 def upload(app, user, args):
-    response = _do_upload(app, user, args.file, args.description)
+    response = _do_upload(app, user, args.file, args.description, None)
 
     msg = "Successfully uploaded media ID <yellow>{}</yellow>, type '<yellow>{}</yellow>'"
 
@@ -312,9 +314,9 @@ def search(app, user, args):
     print_search_results(response)
 
 
-def _do_upload(app, user, file, description):
+def _do_upload(app, user, file, description, thumbnail):
     print_out("Uploading media: <green>{}</green>".format(file.name))
-    return api.upload_media(app, user, file, description=description)
+    return api.upload_media(app, user, file, description=description, thumbnail=thumbnail)
 
 
 def _find_account(app, user, account_name):
diff --git a/toot/console.py b/toot/console.py
index f1f6994..ae98c6c 100644
--- a/toot/console.py
+++ b/toot/console.py
@@ -482,6 +482,12 @@ POST_COMMANDS = [
                 "help": "plain-text description of the media for accessibility "
                         "purposes, one per attached media"
             }),
+            (["--thumbnail"], {
+                "action": "append",
+                "type": FileType("rb"),
+                "help": "path to an image file to serve as media thumbnail, "
+                        "one per attached media"
+            }),
             visibility_arg,
             (["-s", "--sensitive"], {
                 "action": 'store_true',