Currently, when utilizing the SQL Server images in the VM Gallery in Azure, any installations of SQL Server Analysis Services default to Multidimensional. Thus, if you want SSAS Tabular, you have additional work to perform.
I was just chatting with a Senior Program Manager on the SQL Server Analysis Services product team. They currently don’t have anything in their plans for providing SQL Server Gallery Images with SSAS Tabular instead of Multidimensional. We agreed that it is a good idea for that to happen. We also agreed that a Connect suggestion would be a great way to gauge broader community support/appetite for providing Gallery images with Tabular installed.