This is a bit of a hack at the moment, and will give you some false positives, but you can currently “filter” for certain content using the search bar, because it searches the markdown.
Searching for ![ will show you all cards with images.
Similar searches include:
``` : show all cards with code blocks
$$ : show all cards with LaTeX blocks
- [ ] : show all cards with unchecked todos
And so on. We have plans for a more consistent approach in the future, but in the meantime this actually works very effectively.