[Rob Crutchfield]

This may be a very elementary question but I haven't been able to find an answer. I have a simple HTML document which displays a set of Jpeg page images, separated by the BR tag (and nothing else). I convert it to MOBI using Calibre, and upload it to my Kindle (7th generation). On the Kindle, the images are displayed sideways: the long edge of the page is parallel to the short sides of the Kindle screen, so that the pages are very small and only use half the screen. How can I direct the Kindle to display them in portrait orientation? (This Kindle doesn't rotate the display automatically, and I don't find any way to change the orientation in the settings.)

The images display correctly, in portrait orientation, in the Kindle Previewer.

EDIT: Found obvious answer. Is there a way to delete a post?