The read permission allows user to "View pages, list items and download documents. But on publishing sites (guessing from your screen shot) the restricted read is the permission to be used. The restricted read permission level allows users to "View pages and documents. For publishing sites only".
The view only permission is supposed to block users from downloading documents, but if implemented the wrong way (on a group), users can still download documents. The view only permission needs to be set on the individual user.
It is also possible, but not recommended, to change the default permission levels, which make things even more complex.
Default permission levels
Permission levels are collections of permissions that allow users to perform a set of related tasks. SharePoint Server 2010 includes five permission levels by default. You can customize the permissions available in these permission levels (except for the Limited Access and Full Control permission levels), or you can create customized permission levels that contain only the specific permissions you need.
There are other permission levels valid for all sites but team sites:
If you use a site template other than the team site template, you will see a different list of default SharePoint groups. For example, the following table shows additional permission levels provided with the publishing template.
- Restricted Read
- Manage Hierarchy
To manage your own permission levels, there are no less than 33 permissions to work with. But if you can, use the default permission levels.
Reference and more to read: User permissions and permission levels (SharePoint Server 2010)