Gallo is a web application, which lets you display image attachments from Trello cards, as a simple gallery.
It's intended to run as a standalone web application on old devices such as the 1st generation iPad, but should work fine in most modern browsers as well.
The source code is available on Github and released under the MIT license
First of all, you'll need to log in with your Trello account.
Cards will not show up in Gallo by default, however. To make them available, there are a few requirements that need to be met beforehand.
Once cards are available, you should be able to see the parent boards here.
A card must:
Before images are shown for a card, a cover page with a title and an optional date is displayed briefly. These correspond to the card name and due date respectively.