In case I'm about to use an image from Wikimedia Commons (like https://commons.wikimedia.org/wiki/File:Sa-warthog.jpg for example), what exactly does

attribute the work in the manner specified by the author or licensor

mean? There is hardly ever any exact formulation that the autor requires except for the generic CC block.

Would this be sufficient?

Image Sa-warthog.jpg is part of Wikimedia Commons licensed under CC-BY-SA 3.0