The other day someone was saying that all the forms of God that we worship are all man-made. Nobody has seen what God is like. This is partly true. At the same time, in the Sanatana tradition, the Vedas and the Puranas have very clear, explicit descriptions of deities. Ishvara/God is always presented as all powerful, all pervading and limitless, conceived of in various forms for worship, mental or physical. These forms are described in the Vedas and Puranas very clearly. Therefore, the traditional Shilpis, the sculptors who sculpt the temple murtis, follow it very strictly.
Additionally, there are devotees who on the strength of their devotion have the freedom to visualise God as they want to. Bhagavan in his infinite kindness has appeared to them in those forms. For example when Swami Vivekananda as Narendranath approached Ramakrishna Paramahamsa and asked if he had seen God, the reply was – More clearly than I see you. Painters and sculptors in the name of artistic freedom also visualise God, from the very traditional paintings of Ravi Verma to the caricatures of Hussain, we have a wide variety of forms, visualisations, which naturally may confuse or inspire the masses. If you want to see what traditional forms are you have to go to the books that deal with them or go to very traditional temples and see those murtis.
Still, these are all still conceptualisation by the Rishis. Ishvara or God is not an object of perception. You cannot leave yourself out when you understand Ishvara. In the Sanatana vision of Ishvara, he is the most all-inclusive Being. Neither the universe nor the non-devotee stand apart independent of him. Therefore, if you really want to understand Ishvara or God, then you have to approach the pramana that deals with it like the Upanishads and Gita and others in our tradition. That cannot be fully understood in a small article or in social media posts. One has to study in a traditional manner. These articles and posts can only give you some general knowledge.
The writer is the founder of Aarsha Vidya Foundation. You can write to him at aarshavidyaf@gmail.com