It's exciting news for AI artists everywhere: the powerful Flux Kontext is now available to use inside ComfyUI. This opens up a whole new world of fast, high-quality image-to-image editing.
But if you're here, you might have already discovered a frustrating problem. You loaded your image, carefully wrote one of your best prompts, and the result that came back was... strange. Messy. Or maybe it looked nothing like what you wanted.
If that sounds familiar, you're not alone, and the fix is surprisingly simple.
The secret to Flux isn't that it's complicated—it's just different. Unlike other AI models that need you to describe the whole picture, Flux already sees and understands your starting image. It doesn't need you to describe what's already there. It just needs you to tell it what to change.
This guide is built entirely around that one core idea. We will teach you this new, simple way of "talking" to the AI. By the time you're done reading, you will be an expert at writing the perfect flux kontext prompt and can finally start creating the amazing images you had in mind.
How to Write Image-to-Image Prompts for Flux Kontext
When it comes to the Flux Kontext image editing process, the single most important rule to remember is this: the level of detail in your prompt directly controls the outcome. Being more explicit about what you want to change—and what you want to keep—is always the best strategy.
Let's explore how your prompt's precision affects the final image across three levels of editing.
Level 1: Be Specific from the Start
To get predictable, high-quality results from Flux Kontext, your prompts must be specific. Let's look at a common image-to-image generation scenario to see the correct way to structure your command.
Imagine your goal is to change a painting of a quiet street at night into a daytime scene, but you want to preserve its unique artistic feel. To do this successfully, you need to give the AI image to image generator precise instructions.
This is the correct way to write the prompt:
- Prompt: “Change to daytime while maintaining the same style of the painting”
This prompt is effective because it gives two clear and distinct instructions:
- The Action: Change to daytime. This tells the AI the primary goal.
- The Constraint: while maintaining the same style of the painting. This is the crucial part that ensures quality and consistency. It tells the AI what to protect, such as the original brushwork, color palette, and overall mood.
By including a constraint, you remove ambiguity and take full control of the image editing process. This is the fundamental principle you should apply to all your edits: tell the generator what to change in the source image, and just as importantly, tell it what to keep.
Level 2: How to Prompt for Complex Transformations with Flux Kontext
What if your goal involves more than a single change? Flux is designed to handle multiple instructions at once, allowing you to perform complex edits in a single step. The key is to structure your prompt by clearly listing each change while still anchoring it to a core constraint.
Let's say your goal is to transform the painting of a quiet nighttime street into a bustling daytime scene, complete with pedestrians, all while preserving the original artistic style.
This is the correct way to write the prompt for this complex task:
- Prompt: “change the setting to a day time, add a lot of people walking the sidewalk while maintaining the same style of the painting”
This powerful prompt works because it clearly separates multiple actions from the single, overarching rule:
- Action 1: change the setting to a day time.
- Action 2: add a lot of people walking the sidewalk.
- The Constraint: while maintaining the same style of the painting.
By stacking your instructions this way, you command Flux to perform both edits—changing the time and adding people—while applying the "maintain style" rule to the entire transformation. This method allows you to make significant, multi-faceted changes to your image with precision and control.
How Do I Use Style Transfer in Flux Kontext?
Flux allows you to do more than just edit existing elements; you can completely transform the artistic style of an image. This can be done either by describing the style you want in a prompt or by providing another image as a direct reference.
How to Define a Style with Your Prompt
You can change the entire artistic feel of an image using only a text prompt. To do this with precision and control, your instructions must be clear and specific. Vague terms will produce vague results.
Here are four techniques to ensure you get the exact look you want:
- Name the Specific Style. Avoid vague terms like “make it artistic.” Instead, give a direct command like “Transform to a Bauhaus art style” or “Convert to a watercolor painting.”
- Reference Known Artists or Movements. For more precise results, refer to styles the AI will easily recognize, such as “In the style of a Renaissance painting” or “Like a 1960s pop art poster.”
- Describe the Style’s Key Characteristics. If a style name isn’t specific enough, describe the visual elements that define it. For example: “Transform to an oil painting with visible brushstrokes, thick paint texture, and rich color depth.”
- Preserve What Matters. To maintain the image's core structure, explicitly state which elements should not change. This is a crucial step for control. For example: “Change to a pencil sketch style while maintaining the original composition and object placement.”
How to Apply a Style from Another Image
Sometimes, the style you want is easier to show than to describe. Flux allows you to use one image as a "style reference" to generate a completely new image.
To do this, you provide an input image that defines the style you want to copy. Then, you write a prompt that describes the new scene, starting with the command "Using this style...".
For example, using Van Gogh's painting as the style reference, you would write the following prompt:
Prompt: “Using this style, a bunny, a dog, and a cat are having a tea party seated around a small white table.”
This powerful command tells Flux to ignore the content of your reference image (the abstract shapes) and apply only its visual characteristics—like its colors, textures, and brushwork—to the new scene you described in the prompt.
How to Maintain Character Consistency Across Edits
Want to change the background, clothes, or style in a photo but keep the person looking exactly the same? This is all about character consistency, and the trick is simpler than you think.
The most important rule is to always use your original, unaltered photo as the input for every new edit. Don't use the picture you just finished editing. Start fresh with the original each time.
Let's begin with our starting image:
- Input Image: A photo of a woman.
Now, let's try a few different edits. For each one, we'll go back to the original photo to ensure the character stays consistent.
Example 1: Removing an Object
- Start with: The original photo of the woman with the leaf.
- Prompt: “Remove the leaf from her face, making sure to keep her facial features and expression exactly the same.”
Example 2: Changing the Background
- Start with: The original photo of the woman with the leaf.
- Prompt: “Remove the leaf and place this woman on a sunny street in Freiburg, but keep her face and identity exactly the same.”
Example 3: Changing the Clothing
- Start with: The original photo of the woman with the leaf.
- Prompt: “Change this woman's shirt to a red jacket and remove the leaf, making sure to keep her face and hair the same.”
This method is perfect for iterative editing. By always using the original image as your anchor, you can create dozens of variations without ever losing the likeness of your character.
Simple Tips for Good Character Consistency using Flux Kontext
When you write your prompt, just remember three things:
- Point to Your Character. Be specific. Say "the woman with short black hair" instead of just "her."
- Say What You Want to Change. Clearly state the new background, clothing, or action. For example, "put her on a beach" or "change her shirt to blue."
- Tell Flux Kontext to Keep the Person the Same. This is the most important part. End your prompt with a clear instruction like “keep her facial features the same” or “preserve her identity.”
A Common Mistake to Avoid - Using Vague Words Like 'Her'
The AI has no memory of your last edit. Using a vague word like "her" by itself will not work.
- Don't do this: “Now put her on a beach.” (The AI won't know who "her" is.)
- Do this instead: “Take the woman from the image and put her on a beach, keeping her appearance the same.”
How to Edit Text in an Image with Flux Kontext
Need to update a sign, change a label on a product, or correct a typo in a poster? Flux lets you edit text directly within an image, saving you from having to recreate it from scratch.
The most effective way to edit text is to tell the AI exactly what to replace. Use quotation marks in your prompt to be precise.
The Best Prompt to Use: Replace "[original text]" with "[new text]"
Here are a few examples showing how it works.
Example 1: Swapping One Word for Another
Let's start with an image that has the text "MimicPC" on it. We want to replace it with "FLUX."
- Prompt: Replace "MimicPC" with "FLUX"
Example 2: Changing a Poster Title
Here, we have a poster with the title "GALACTIC ODYSSEY," and we want to change it to "FLUX KONTEXT."
- Prompt: Replace "GALACTIC ODYSSEY" with "FLUX KONTEXT"
Tips for Better Text Editing
To get the best results, keep these simple practices in mind:
- Start with Clear Fonts. The AI works best with clear, readable fonts. It may struggle to accurately edit very complex or handwritten styles.
- Ask to Keep the Style. If you want the new text to match the old style, just say so in the prompt. For example: “Replace 'GALACTIC ODYSSEY' with 'FLUX KONTEXT' while keeping the same font and color.”
- Keep Text Length Similar. Try to keep your new text about the same length as the original. Swapping a short word for a very long sentence can sometimes disrupt the image's layout.
How to Fix Common Editing Problems
Sometimes, an edit doesn't turn out exactly how you planned. If the AI is changing parts of the image you wanted to keep, the solution is almost always to be more specific in your prompt.
The Golden Rule: If the AI changes something you wanted to keep, simply add a command to your prompt telling it to preserve that element.
- "...but keep everything else black and white."
- "...and don't change anything else in the image."
Here are fixes for the most common issues.
Problem 1: Why the Person's Face Changes Too Much
When you change a person's clothes or put them in a new scene, their face and identity can sometimes change, too.
The Fix: Use precise words. Instead of asking to "transform" the person, ask to "change their clothes" or "add armor." Most importantly, add a command to keep their face the same.
Example: Making a Man into a Viking
- Input Image: A photo of a man.
- Bad Prompt: “Transform this man into a Viking.”
- Good Prompt: “Change the man's clothes to Viking armor, but keep his face, hair, and expression exactly the same.”
Why this happens: The word "transform" signals to the AI that a complete change is okay. Verbs like "change clothes" or "add" are more specific and give you better control.
Problem 2: Why the Person Moves or Changes Size
When you change the background, the main subject can sometimes shift position, change size, or the camera angle might look different.
The Fix: Explicitly tell the AI to lock the subject in place. Command it to keep the person in the exact same position, scale, and pose.
Example: Changing the Background to a Beach
- Input Image: A photo of a person standing.
- Bad Prompt: “Put him on a sunny beach.”
- Good Prompt: “Change the background to a sunny beach, but keep the person in the exact same position, scale, and pose. Do not change the camera angle.”
Why this happens: A vague instruction like "put him on a beach" lets the AI guess what a "beach photo" should look like. By giving it strict rules about position and scale, you remove the guesswork.
Problem 3: Why the Style Looks Wrong or Loses Detail
When you apply an artistic style, like turning a photo into a sketch, the result can sometimes look too simple or lose important details from the original image.
The Fix: Describe the style you want in more detail. Instead of just "make it a sketch," describe the kind of sketch you want.
Example: Turning a Street Scene into a Sketch
- Input Image: A photo of a street with cars and buildings.
- Bad Prompt: “Make it a sketch.”
- Good Prompt: “Convert this photo into a detailed pencil sketch. Use cross-hatching for the shadows and make sure to keep the cars and buildings from the original image.”
Why this happens: A simple prompt gets a simple result. By providing more descriptive keywords (like "detailed," "cross-hatching," "keep the cars"), you guide the AI toward a higher-quality, more faithful result.
Conclusion: Key Takeaways for Perfect Edits
Getting the perfect result is all about giving clear instructions. If you remember these key practices, you'll be able to edit your images with precision and control.
- Be Specific. When editing existing images, precise language helps generate images that are far more accurate. Instead of "red car," try "shiny, cherry-red sports car."
- Start Simple, Then Build. Make one change at a time. First, change the clothes. Then, using that new image, change the background. Flux is excellent for this kind of step-by-step editing.
- Tell Flux Kontext What to Keep. If you don't want something to change, say so directly. Add “...but keep the person's face exactly the same” to your prompt to protect important features.
- Avoid Vague Words like 'It' or 'Her'. The AI has no memory of past edits. Always refer to "the woman with short black hair" or "the building on the left" instead of pronouns.
- Use Quotation Marks for Text. The best way to change text is to be exact. Use the format: Replace "MimicPC" with "FLUX".
- Lock Your Composition. To prevent your subject from moving or changing size, add “...and keep the person in the exact same position, scale, and camera angle.”
- Choose Your Verbs Carefully. The words you use matter. "Change the shirt to blue" gives you more control and better results than "transform the person."
Ready to Try It Yourself?
To help you get started right away, MimicPC offers a pre-built Flux Kontext dev workflow for ComfyUI.
If you're not familiar with ComfyUI or prefer a more straightforward experience, you can also use FLUX Kontext Pro, which provides a very simple and user-friendly interface.
And if you're looking for more inspiration, check out our other blog post detailing 15 powerful use cases for Flux Kontext to see what's possible.