Image size does not make use of available space

[MichaelNMaggs]

When the images are viewed as a grid of thumbnails, they are always shown at very small size given the space that is available. Regardless of the thumbnail size, there is always an extremely wide grey border which represents wasted space. Similarly, the information screen has a huge black border. In both cases it would be better to use the wasted space in order to show larger images.

(previously reported by email on 23/3/17)