I think https://pulumi.io/reference/crosswalk/aws/ecs/#ecs-tasks-containers-and-services has a syntax error. It shows

awsx.ecs.Image.fromPath("<path-to-dockerfile>")

but the docs (and a syntax error on my end) say

fromPath

requires two arguments.

Thanks. I opened an issue at https://github.com/pulumi/docs/issues/1230.