If I add this statement to a logbook config file:

Show attachments = 0

When viewing and individual entry, attached images are not displayed, which is as intended, but the links Show/Hide and Show All/Hide All are still displayed although they do nothing when clicked except switch between Show and Hide. Clicking on an image opens it in a separate window.

Could you make show/hide and show/hide all work? This way, by default the images are not displayed, but the default could be overridden on a case by case basis as desired, and the images displayed inline in the same window with the entry.