I’m going to make a lot of assumptions here:

• that image generator thing posts directly to lemmy (otherwise why would it be relevant to mention?)
• that image generator thing posts from whatever IP address (and thus country) it’s running in, most likely a different one than yours)
• you added a comment soon after posting the image, from your own app/browser, and thus your IP address

Lemmy (or specifically .world?) saw this as you posting twice in rapid succession from two different locations, which it associates with vpn spambots, and voila?