some of our images in the html/text module where missing a '/' at the beginning which was causing the paths to be something like: portal/id/portal/id/image . we ran this query and that fixed all our images:

Update [DnnPortals].[dbo].[HtmlText]
set content = cast(replace(cast(content as nvarchar(max)),'src="portals/','src="/portals/') as ntext)
WHERE Content LIKE '%src="portals/%'

hope this helps someone.