Back in 2014, Matt Cutts formerly of Google talked about meta data in images and basically said they reserve the right to use it, that Google is able to parse it out but did not comment if they use it for rankings or display or both. Well, he did say they did use it for showing more details about the photos in the image thumbnails on Google Image search but did not comment about the ranking component.
Here is that video:
John Mueller of Google was asked about this the other day and he said on Twitter "this is still the same as before." So am still a bit confused on this topic. :)
Truth is, this should be easy to test - at least the indexing and ranking component.
Forum discussion at Twitter.
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