diff --git a/web/app.py b/web/app.py
index 4abec5b..65a8839 100644
--- a/web/app.py
+++ b/web/app.py
@@ -1,5 +1,6 @@
 """Flask app: status/preview page + one settings form per screen + rotation settings."""
 
+import logging
 from io import BytesIO
 
 import requests
@@ -9,9 +10,11 @@ from werkzeug.utils import secure_filename
 
 from screens.picture import UPLOAD_DIR
 
+logger = logging.getLogger(__name__)
+
 ALLOWED_IMAGE_EXTENSIONS = {"png", "jpg", "jpeg", "gif", "bmp", "webp"}
 PIL_FORMAT_TO_EXT = {"JPEG": "jpg", "PNG": "png", "GIF": "gif", "BMP": "bmp", "WEBP": "webp"}
-PICTURE_URL_TIMEOUT = 15
+PICTURE_URL_TIMEOUT = 30  # a one-time download at save-time, not a recurring poll -- fine to be generous
 MAX_SCHEDULE_RULES = 4
 PICTURE_URL_HEADERS = {
     "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36",
@@ -244,12 +247,25 @@ def create_app(config, screens: dict, scheduler) -> Flask:
                     response = requests.get(url, timeout=PICTURE_URL_TIMEOUT, headers=PICTURE_URL_HEADERS)
                     response.raise_for_status()
                     content = response.content
-                    fmt = Image.open(BytesIO(content)).format
-                except (requests.exceptions.RequestException, OSError):
                     fmt = None
+                except requests.exceptions.Timeout:
+                    content = fmt = None
+                    error = f"Timed out downloading that URL after {PICTURE_URL_TIMEOUT}s -- the host might be slow or blocking this server."
+                except requests.exceptions.RequestException as exc:
+                    content = fmt = None
+                    logger.warning("Picture URL download failed for %s: %s", url, exc)
+                    error = f"Could not download that URL -- {exc}"
+                else:
+                    try:
+                        fmt = Image.open(BytesIO(content)).format
+                    except OSError as exc:
+                        logger.warning("Picture URL %s downloaded but didn't decode as an image: %s", url, exc)
+                        fmt = None
+
                 ext = PIL_FORMAT_TO_EXT.get(fmt or "")
                 if not ext:
-                    error = "Could not download a valid image from that URL -- try a different link, or upload a file instead."
+                    if not error:
+                        error = "That URL doesn't look like a valid image -- try a different link, or upload a file instead."
                 else:
                     UPLOAD_DIR.mkdir(parents=True, exist_ok=True)
                     # Only one picture is ever active -- clear any previous