Page Icon displaying broken image icon

When loading into my campaign, when I open the ribbon one of the pages I created (which is the most detailed map I've ever made) doesn't show a thumbnail. In its place there is a transparent box, with the broken image icon (like when an IMG HTML code references a missing image)... how can I fix this without having to rebuild the map?

The page icon is based on the largest image on the page. A technique or tip is, stretch a copy of the image you want as your thumbnail, into the largest image on the page, and use right-click "To Back" to hide that image in the background behind other graphics-maps-tiles. I hope this helps. If this does not resolve your issue and you want to troubleshoot the question of why there is a broken image icon, please post again and I will try to help with finding an answer for that. EDIT: Documentation now added to wiki, <a href="https://wiki.roll20.net/Page_Toolbar#Page_Icons" rel="nofollow">https://wiki.roll20.net/Page_Toolbar#Page_Icons</a>

That worked perfectly... thank you!