1. Go to Google Image Search and click on the little camera icon.

https://i.imgur.com/ge9dLBj.png

Enter a URL of one of the images of your website and click search.

As you can see, there are other websites using this image.

2. Contact the webmaster of the website that’s using your image and ask them to link back to you.

It works because it’s your image and they are using it without giving you any link (credit).

Here is a reach out template that might help you:

“Hey [Name]
I found out that you are using my image on [article name].
The image link is: [Image Link]
Thank you for using my image as a resource to your blog readers. But I found that you haven’t given a credit link for the image.
I would love if you give a link back to my website for the image credits.
Thank You
[Your Name]
Happy hunting!”

Bonus hack:
Create your profile and start uploading quality pictures on UnSplash.Com

Check every day your statistics and do the image reverse search on Google for your most popular pictures.

Shoot an email to the blogger who used your picture and ask him politely to add credits to your picture with your website link.

I get around 30% response rate and usually, they add the link afterward.