Retry image download

Some images may be too large for the IIIF server when requesting full size. This MR implements a fallback to the maximum size allowed in case the download failed.

dan/datasets/extract/utils.py

@@ -57,7 +57,7 @@ def download_image(url):
     try:
         resp = _retried_request(url)
     except requests.HTTPError as e:
-        if 400 <= e.response.status_code < 500:
+        if "/full/" in url and 400 <= e.response.status_code < 500:
             # Retry with max instead of full as IIIF size
             resp = _retried_request(url.replace("/full/", "/max/"))
         else: