MAL-Sync is a powerful userscript, which enables automatic episode tracking between MyAnimeList and multiple anime streaming websites.
Even more Powerfull are MAL-Syncs browser Extensions:
What else can it do?
Displays the last opened viewing page and a link to the next episode on your MAL Bookmarks page
miniMAL, a frame which can be toggled by a floating button which appears in the lower right of your screen on supported streaming sites.
When visiting the MAL-page for an anime/manga, you will in your left sidebar have direct links to the supported sites.
You will also have larger thumbnails on MAL, with options to choose your preferred size from a settings-tab in miniMAL.