full screen gallery view

hi, is there a possibility to view pictures in full screen - full size? I'm uploading originals and I know all pictures are resized but what's the point not to see a picture in a big size when you have such picture to show?
portrait format is viewed from the top to bottom however landscape pictures (weather viewed in gallery as single picture or slideshow) are visible just in a really small format. I'm not sure if I'm doing something wrong or there isn't simply such an option which would be a problem... I haven't found any discussion about this topic and I'm really surprised. Please advise