By using the command az acr import
means that you can import an image to an Azure Container Registry from another Container Registry. So you should have container images from a public registry or another Azure container registry, in the same or a different Azure subscription or tenant or from a non-Azure private container registry. Read Import container images to a container registry for more details.
In this case, if you have built the images locally, you can push the images directly to the ACR instead of using import. You can make it as the Tutorial: Create an Azure container registry and push a container image:
log in to your Azure Container Registry instance
az acr login --name <acrName>
tag the image with the full name of the registry's login server.
docker tag <localImage> <acrLoginServer>/<acrRepository>:<tag>
Push image to Azure Container Registry
docker push <acrLoginServer>/<acrRepository>:<tag>
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