You’ll need any and all references in the database to the old folder to be changed — this would be not just images but any internal links as well. If you’d rather not dive into the .sql file yourself, the easiest thing is probably to use a plugin like Velvet Blues ( https://wordpress.org/plugins/velvet-blues-update-urls/ ). It will change all the old urls to the new ones.
This is what you’re wanting, correct?
If there are any hardcoded paths in your template files (hopefully not!) you’ll have to change those manually. Velvet Blues just addresses the database.