We know Google discovers and displays images very quickly in their search index, but once it is indexed, Google may take a really long time to discover the update.
For example, let's say you upload green-flowers.jpg to your server and Google finds it. Then a few days later you realize you actually uploaded them as red flowers, so you repost the green flower image on the same green-flowers.jpg filename.
John Mueller from Google said it can take Google months, or maybe longer to update that image in their Google Image search index.
John wrote on Twitter, "images don't change often, so we don't reindex them frequently." When questioned how long that can take, John added, "depends, maybe on the order of months. Also, indexing isn't guaranteed, so you can't assume it'll always happen."
Here are the tweets:
@AndyNRodgers images don't change often, so we don't reindex them frequently. It would take a while, but should work.
— John Mueller (@JohnMu) January 25, 2016@AndyNRodgers Depends, maybe on the order of months. Also, indexing isn't guaranteed, so you can't assume it'll always happen.
— John Mueller (@JohnMu) January 25, 2016Forum discussion at Twitter.
