Gallery widget can display the images of one folder in gallery.
 
mcu/venusmmi/app/Cosmos/Widget       vapp_widget_gallery_*.*   Gallery widget source code file
mcu/venusmmi/app/Cosmos/Widget/res  app_widget_gallery_*.res  Gallery widget resource file
plutommi/Customer/Images/COSMOS*/MainLCD/Default/Widget/Gallery  *.*     Image files 
__MMI_FTO_GALLERY__   Available sync with gallery 
__MMI_MAINLCD_480X800__
__MMI_MAINLCD_320X480__ 
VappWidgetGallery
–Widget  virtual funciton implementation
–Composed components

VappWidgetGalleryViewer
–Core of gallery widget
–Responsible for slide show

VappWidgetGalleryControlBar
–Handle control bar activity

VappWidgetGalleryViewerPanel
–Show Photo frame
–Record photo information

VappGalleryMediaListMediaCache
–Integrate with fmgr and media cache service