The APP is primarily made for taking photos and uploading them to Billion Graves. It was never really planned to be a place you would store photos. The photos you take with BG app get compressed and are not the same quality as you would have from just using your camera. The only APP option is to delete all photos. If you are a bit more computer savy, you can connect your phone to a PC, and then find the place where BG stores the photos and delete them from there. I have an Android phone and the loacation is "\Phone\Android\data\com.och.BillionGraves\bg_images". You will need to restart the BG APP after deleting the photos or it will get well confused.