Which file format is used as a virtual appliance in virtualization applications?

The file format associated with virtual appliances in virtualization applications is the OVA format. An OVA (Open Virtual Appliance) file is essentially a packaged file that contains all the necessary components, including the OVF (Open Virtualization Format) descriptor file and any associated disk images, configurations, and other metadata required for the virtual machine's operation.

Using OVA files simplifies the process of deploying virtual machines, as it allows users to import a single file that brings along all the required elements rather than handling multiple files separately.

In contrast, the OVF format is primarily a specification used for packaging and distributing virtual machines, while VMDK files are specific to VMware's virtual disk format. The IMG format is more general and can represent disk images for various other systems, making OVA the most appropriate choice for this context.