Image metadata is text information that is embedded or contained in an image file. This may include data such as the creator, creation date, location, contact information for licensors of the image, headline, title, captions, keywords, copyright information and rights usage terms. This can be updated in image editing programs such as Photoshop.
Recently a student in my SEO training course asked if image metadata should be updated for SEO purposes. Recalling Matt Cutts' (former head of Google’s Webspam team) explanation, I advised that it does not effect SEO.
It has been 3 years, and to be absolutely sure I checked with Webmaster Trends Analyst at Google, John Mu:
It's great to see someone who prepared :). This is still the same as before.
— John ☆.o(≧▽≦)o.☆ (@JohnMu) September 15, 2017
So Matt Cutts' advice remains the same: Don't worry about adding image metadata if it’s not there already.