Hi, @humbledeen. Are both of the images you were using yours? If yes, you should have mentioned it, maybe put a post-script, stating your ownership of said, images. If both of the images wasn't yours, you need to cite the source along with the author and license version (whichever required according to the license version). Please refer here if you're not familiar with what I was talking about.

Nice article by the way. If you have any problem regarding STEM-related articles, you can join steemSTEM Discord Channel and we will be glad to assist you.