Copy/paste the uploader files from ‘app’ and ‘skin’ folder to the root direction. Make sure to overwrite directories: ‘app’ and ‘skin’ in the Magento 1.9 directory.
After installing the directories, log in to the admin panel.
- Reindex the Magento website: System > Index Management > Select All > Reindex Data and Submit
- Clear Magento cache: System > Cache Management > Select All: Enable
- Then: Refresh: Submit
- Log out and Log back in
- Go to: System > Configuration > HTML5 uploader > General Settings > Enable: Yes
For more info click here.
You can download the Maven HTML5 uploader extension here.