Thanks for the quick response. That's rather unfortunate, since that CSS snippet you posted is part of Jetpack, a rather popular plugin. I tried switching to a vertical image, but that doesn't work well either - it doesn't show the image on the splash page then on my laptop. Is there a particular size I should crop an image to, for it to definitely fit? That would be a bit cumbersome, but could at least solve the problem. Is there perhaps another solution that is more elegant? Changing the CSS of the plugin manually isn't ideal, of course, since it could have unintended consequences (as you mentioned), but would also get overwritten the next time I update that plugin.

Looks like the offending CSS is part of the Mobile module in Jetpack. Therefore, switching to a theme that is already mobile-ready (i.e responsive) could allow me to disable it, at which point the splash screen would hopefully not show a cropped image. A bit roundabout though...

For now, I have had to switch the gallery back to Simpleviewer, since the splash screen with the cropped image does not look good. I will only be able to use Juicebox if there is a reasonable solution to this issue.

Thanks for the quick response! Yes, that worked great. Would you consider adding control over this directly in the interface? I'm concerned that I'll forget to re-make the changes when I update. This could potentially be useful to others - one might want to show just the title/alt, just the description, both, or none. Thoughts?

PS: In the meantime I purchased the Pro version.