Viewing A Photo In Landscape Orientation - HTC Merge User Manual

From the filmstrip view, press MENU and then tap Grid view to browse
photos and videos by thumbnails. Slide your finger up or down to
scroll through the thumbnails.
To change back to displaying photos and videos in a filmstrip, press
MENU and then tap Filmstrip view.
Whether you're in filmstrip or grid view, you can press and hold on

a photo or video to open a selection menu and choose what to do
with the photo or video.
If you want to select another album, tap

application's Albums screen.

Viewing a photo in landscape orientation

Turn your phone sideways to the left to view the picture in landscape
mode. The picture orientation automatically adjusts to how you hold
the phone.
Gallery 
to return to the Gallery