Attach images to cards

[birdisito]

Attach images to cards, it's a no-brainer. Super useful and necessary, especially for people working on visual tasks like art.

[trobonox]

Thanks for the suggestion! This is planned and quite high on my list of priorities for the next major release, see #519
Unfortunately I havent had much time lately and there are lots of small issues that need to be worked on first, so this will take a while to implement.