Related to {T4863}, we've gotten requests from various designers, to enable an optional view that shows a "thumbnail of attachments" on the workboard cards. This would assist more visually-oriented people in finding/triaging tasks.
It's a core feature of Trello, as shown here:
* from https://trello.com/b/EXtVTJxJ/mediawiki-ui-use-phabricator
{F865711}
* from https://trello.com/b/kpRalFpn/user-experience
{F865712}
-----
For reference: The way Trello does it, is by giving users an option to "Make cover" or "Remove cover". I believe it makes the first attachment a "cover" image by default.
{F865718}
Then each board has a "Card Cover Images Enabled" setting.
{F865724}
Hope that helps. :-)