Hands with six fingers, eyes looking in different directions, distorted facial features—these are the classic, tell-tale signs of an AI-generated image. But why do AI models, which can render breathtakingly complex landscapes, struggle with basic human anatomy? The reason is twofold. First, hands and faces are incredibly complex and expressive, with a huge range of possible positions and configurations. The AI has to learn all of them from 2D images, which is a difficult task. Second, in most of the training data (photos on the internet), hands and faces are a relatively small part of the overall image. The AI, therefore, has less clear, high-resolution data to learn from compared to, say, trees or skies. This leads to it sometimes getting the details wrong, resulting in the infamous 'AI hands' or wonky eyes.
Why AI Struggles with Anatomy
Hands with six fingers, eyes looking in different directions, distorted facial features—these are the classic, tell-tale signs of an AI-generated image. But why do AI models, which can render breathtakingly complex landscapes, struggle with basic human anatomy? The reason is twofold. First, hands and faces are incredibly complex and expressive, with a huge range of possible positions and configurations. The AI has to learn all of them from 2D images, which is a difficult task. Second, in most of the training data (photos on the internet), hands and faces are a relatively small part of the overall image. The AI, therefore, has less clear, high-resolution data to learn from compared to, say, trees or skies. This leads to it sometimes getting the details wrong, resulting in the infamous 'AI hands' or wonky eyes.
Strategy 1: Proactive Prompting with Negative Prompts
The first line of defense is to be proactive in your prompting. You can use negative prompts to tell the AI which specific flaws to avoid before it even starts generating.
Your Anatomical 'Guard Rail' Prompt
Create a standard negative prompt that you use for any image involving humans. This acts as a 'guard rail,' steering the AI away from its most common anatomical mistakes. A strong anatomical negative prompt would include:
`extra fingers, mutated hands, poorly drawn hands, poorly drawn face, deformed, ugly, bad anatomy, disfigured, extra limbs, fused fingers, too many fingers, long neck, malformed limbs`
While this won't solve the problem every single time, it significantly increases your success rate and reduces the number of generations you have to discard due to obvious flaws.
Strategy 2: The Art of Hiding and Suggesting
If hands are not the main focus of your image, sometimes the easiest solution is to cleverly hide them. You can incorporate this into your main prompt.
Prompting to Conceal
Try prompts where the hands are naturally out of sight. For example: `a man standing with his hands in his pockets`, `a woman with her arms crossed`, or `a knight holding a large shield that covers his hands`. This is a practical workaround when you want to avoid the 'hand lottery' altogether for a particular image.
Strategy 3: The Power of Inpainting (The Ultimate Fix)
This is the most powerful and professional technique for fixing flaws. Inpainting (or 'inpainting masks') is a feature in many advanced AI platforms that allows you to selectively regenerate a small part of an image while keeping the rest of it exactly the same.
The Inpainting Workflow
1. Generate Your Image
First, generate your image as you normally would. Find one that is almost perfect, but has a specific flaw, like a badly drawn hand.
2. Mask the Problem Area
Using the inpainting tool, you will use a digital brush to 'mask' (paint over) the flawed area. For a bad hand, you would carefully paint over the entire hand and wrist.
3. Write a Targeted Prompt
Now, you write a new, highly specific prompt just for the masked area. You would change your original prompt to something very simple and focused, like: `a perfectly formed, realistic human hand` or `a detailed, anatomically correct eye`. You are giving the AI a very small, very specific task.
4. Regenerate
The AI will now regenerate *only* the part of the image that you masked, using your new targeted prompt. It will try to blend the newly generated hand or eye seamlessly with the rest of the existing image. You might need to try this a few times to get a perfect result, but it gives you an incredible level of surgical control to fix otherwise unusable images.
