AI Detection vs. Blocklists: Two Ways to Block AI Images

Ad blockers nailed repeat offenders early on. A tracker domain shows up on a hundred sites, someone adds it to a filter list, and every browser subscribed to that list blocks it from then on.

AI-generated images broke that math. There's no single domain serving synthetic photos. A brand-new account can post a completely new image every few minutes, and nothing about that pattern looks like a repeat offense.

That gap is why two different approaches now exist to block AI images. One is the old model: a running list of known accounts, domains, and tags, kept current by volunteers who flag new offenders as they turn up. It works, as far as it goes.

The other skips the list entirely. It looks at the image itself, checking for the patterns an image generator leaves behind, no matter who posted it or how new the account is.

Blocking AI Images: Key Takeaways

• Blocklists filter by account, domain, hashtag, or caption text.
• Detection skips all of that and analyzes the image itself, pixel by pixel.
• A blocklist can't act until someone reports an account, so a brand-new account with a clean history passes through untouched, no matter how many AI images it's posted.
• New generators don't need to be cataloged before detection can catch them.
• Detection costs real compute per image. A blocklist lookup is close to instant.
• AI Blocker runs detection instead of a list, checking every image against AI or Not's model. It's free to install from the Chrome Web Store.

How Blocklists Block AI Content

Community-maintained blocklists for ad blockers existed long before generative AI, built to catch trackers and malicious domains. Extensions that filter AI content borrowed that architecture. An entry might be an account known for posting AI art, a domain hosting generator output, a hashtag tied to synthetic images, or a keyword filter tuned to captions that mention being AI-made.

A volunteer, or a small team, maintains the list. Users flag new offenders, the list gets updated on some cadence, and every subscribed browser inherits the update. It's the same model spam filtering used in the early internet: crowd-reported, unpaid, and only as current as its last sync.

How AI Image Detection Works

Detection skips the list entirely. A model looks at the image itself and checks for the statistical patterns image generators tend to leave behind. Those show up as irregularities in texture, compression, and pixel-level structure, nearly invisible to a human eye but consistent enough for a trained model to catch.

AI Blocker's detection runs on AI or Not, which analyzes each image for those patterns instead of checking it against a list of known posters. The account itself doesn't matter to it. A photo posted five minutes ago by a brand-new account gets the same scrutiny as one from an account that's been posting for years.

Where Blocklists Break Down

A list is only as good as what's already been reported. That has consequences for anyone counting on it.

• New accounts. Content from a fresh account has no history on any list yet, so it passes through until somebody notices and flags it.
• Domain rotation. Block one domain and the operation moves to a new one the same day, sometimes the same name with a single character swapped. The list is permanently playing catch-up.
• Decay. Lists need continuous upkeep. An entry nobody maintains goes stale, missing accounts that renamed, merged, or moved platforms.
• Wrongful listings. A human artist whose style gets mistaken for AI, or who gets reported out of spite, can end up filtered with no simple way to argue their way off.
• Caption stripping. A keyword filter catches a caption that says "made with AI." It misses the same image reposted with the caption stripped off.

None of that makes blocklists pointless. They're cheap and effective against known repeat offenders. The problem is what happens outside that lane.

Where Detection Breaks Down

Detection breaks down in different ways.

• False positives. Heavily processed real photography, certain painting or rendering styles, and unusual lighting can occasionally get flagged when nothing artificial was involved.
• False negatives. An image edited enough after generation, or produced by a method that leaves fewer traces, can slip through unflagged.
• Compute cost. Analyzing an image takes processing time. On a page with a hundred images, that adds up in a way a list lookup never does.
• No shared memory. Each image gets evaluated on its own terms, so seeing the same generated image twice doesn't make the second check faster unless something else is caching the result.

Which AI Blocking Approach Fits You

If you spend most of your time on a handful of platforms with active reporting communities, a blocklist for those accounts still earns its keep. It's cheap to run and good at exactly what it's designed for. Step outside that circle, though, a random site, an account nobody's reported yet, and the list has nothing left to check against.

Most people don't actually choose between the two. They install a browser extension, never look at what's running under the hood, and find out which model it uses only when something slips through.

AI Blocker takes the detection route by default, checking every image on the page and blurring the ones flagged as AI-generated, with a click to reveal. It also checks highlighted text for AI writing and analyzes uploaded audio or video, deleting whatever you upload right after the check runs. It's a free install from the Chrome Web Store.

The list-versus-detection split above is most of what separates an actual ai blocker from a plain content filter. It's also most of how to block ai content once it's already loaded on your screen. The same tension shows up in reverse, in keeping ai bots from scraping your own site.

Blocking AI Images FAQ

What Is the Best Way to Block AI Images?

There isn't one method that covers everything. Blocklists work well against known repeat accounts and cost almost nothing to run. Detection works on any image from any account because it checks the image itself, generalizing better as new accounts and generators appear.

Do AI Blocklists Work?

Yes, within their limits. A blocklist catches accounts, domains, and tags already reported and added to the list. It won't catch a brand-new account, a rotated domain, or a caption-stripped image, since none of those have anything on the list to match yet.

How Does AI Image Detection Work?

A detection model looks for the fingerprints an image generator leaves in the pixels, patterns invisible to the eye but reliable enough for a trained model to flag. AI Blocker's detection is powered by AI or Not, which checks images this way instead of comparing them to a list of known posters.

Can I Block AI Images for Free?

Yes. AI Blocker is free to install from the Chrome Web Store, and it checks every image on a page and blurs the ones detected as AI-generated, with a click to reveal them if you choose.

A blocklist can only block what somebody already reported. The account posting a fresh batch of AI images tonight doesn't have a name on any list yet, and it won't until someone notices. Detection doesn't wait for that.