STORY: The video showed three soldiers raising a large Ukrainian flag on the island, from which Russian forces withdrew on June 30 after coming under heavy bombardment from Ukrainian artillery.
Reuters was able to verify the location of the material by matching buildings and terrain to file and satellite images.
Russia's defence ministry said on Thursday a Russian warplane struck and killed an unspecified number of Ukrainian troops on Snake Island after they landed there to raise the Ukrainian flag.
The tiny island, captured by Russia from Ukraine at the start of the war in February, is strategically important because of its proximity to sea lanes close to Ukraine's port of Odesa.
Russia said it had pulled out from Snake Island last week as a "gesture of goodwill" to show it was not obstructing United Nations attempts to open a humanitarian corridor allowing grain to be shipped from Ukraine.
Ukraine said it had driven the Russian forces out after an artillery and missile assault.