I'm looking at a global, permanent solution to ensure that image files are displayed in full on my Kobo Aura HD. Opening a book in Calibre Ebook Viewer displays images at full-frame, but in Kobo all image files within books (covers are fine) are always so tiny. Here are two pictures of the same book & page, top is from Calibre, bottom is on Aura HD:

Calibre Ebook Viewer:

Aura HD:
Any help would be greatly appreciated, as this is a major annoyance for me given that I read a lot of historical books and those have tons of maps and images that I simply can't view. Thanks!