Hi @Hoangmnsd, exactly as you mentioned, "Azure Application" solution template or managed app offer type needs and ARM template which creates Azure resources that constitute the actual application. Some of the resources could be virtual machines. If the virtual machine can be created from the base images (e.g. CentOS, Ubuntu, or some version of Windows) the template imageReference would point to that image's publisher:offer:sku:version. If on the other hand, the application needs to use a "custom VM image" that image must be published into Azure Marketplace as a VM Offer (it can be marked as "hidden" so that it does not appear in marketplace UI for standalone deployment). Azure Application ARM template cannot refer to the image in the publisher/ISV's Shared Image Gallery (SIG) since that image is not available as part of the public marketplace gallery of images. Hope this helps!