Filenames, like the following, are common examples of what should be avoided:
Images should have meaningful filenames without overly long paths, e.g.
Write keyword-rich alt text (alternative texts), shouldn’t be long, but little descriptive, using keywords
Make sure that images are placed near the relevant text because of not confusing search engines. Search engines assess what page the image is on and the content around the image to dissect important information about the subject matter of your image.
Use commonly supported file types like Ex: .jpeg or .png
Create separate sitemap only for images (excluding thumbelina)
Submit to Google webmaster sitemaps to index
Over 1% of the image requests on a daily basis are now referrals from Google and this percentage is increasing!
This highlights the importance of images as part of an SEO strategy.