The “Resolutions” dialog box of the Windows 7 VIEWER → Settings →Resolutions... allows the users to use up to two resolutions. The client’s native resolution can be enable and use by checking the box of “Native Screen Resolutions”. Then the user can also add another resolution by selecting one of the typical screen resolutions on the combo box.

It's also available on other viewer apps.

Android VIEWER → Menu → Settings → Resolution.

iOS VIEWER→ Settings → Resolution.

Windows Store VIEWER → Settings → Display.