I think there is a big difference between Machine generated images and photoshop/canva ones. In machine generated you just input a set of words and description, and it is generated automatically. With photoshop/canva, there is still more effort from the user, like choosing the image, arranging them, then editing. Additionally, I have seen authors explicitly say the image was generated in Canva, even before AI generated images were a thing. People frequently provide the source of their images when it is ambiguous. I have seen people say "I took this image", or provide a link to the source if it is taken online.

From the Hivewatcher comment, it seems you not only used machine generated art, but the article itself was machine generated. If it was just the art, you also did not provide a source.