I am happy about that, that you used my image, , but you did not give me any credit for it. I have the Attribution license on the image so you can use it, but you need to give me the credit for it (make a link on the image that links it to my original one and/or write somewhere: Photo by DejanH and link it.
Here are rules of using this particular image, where it says: "Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use." https://creativecommons.org/licenses/by-nc-nd/2.0/