You should use local artwork to avoid repeated artwork downloads. You could look at mklocal.py, or the Artwork Beef add-on, as either will download the remote artwork alongside your movies.
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.