Do nearby raids only show silhouettes?
Solution 1:
In a recent update, this has been changed to display the Pokémon rather than the silhouettes based of if you've captured the Pokémon or not.
Since I have captured Magmar, it shows the Pokémon, but with Raikou uncaptured, it displays the silhouette.
Solution 2:
All ongoing Pokemon Raids are depicted in silhouettes. All pending Raids are depicted as an egg. This is shown through this sort of search: Can you see any full colour Pokemon Raid Bosses? Doesn't look like it. However, this may change in the future.