Runway yesterday unlocked the "Gen-4 References" feature in all paid plans. This allows users to insert consistent characters, locations, and other objects into virtual clips without needing any special technical skills.

Runway Gen-4 References – Now Available in All Paid Plans
For some time now, references have been used in various AI models to use photos, generated images, 3D models, or selfies to create an artificial image based on them. A problem that has arisen so far is character consistency. Although artificially generated images often have a great similarity to the reference, they are still usually subject to certain statistical deviations. For example, if you used a photo of an actor as a reference spread over several scenes, they previously looked a little different in each scene.
As the new sample clips from Gen-4 now prove, the problem of consistent characters is well on its way to being solved soon. The results of the new function in Gen-4 are already convincing in many cases, as can be seen, for example, in this longer demo clip:
Currently, the new Gen-4 references work best with people and locations, but Runway promises to work with other objects in the near future.
And if you are interested in how to use the whole thing in practice, you can find a small workshop here that explains the basic operation in Runway: