How to Use the FLUX AI Image Generator Online

This guide walks you through using FLUX online to turn a text description into an image, covering everything from writing your first prompt to getting a result you can actually use.

Quick answer

FLUX is a family of text-to-image models known for accurate prompt following and clean, realistic output. To use it online, you write a description of what you want, choose your settings, and generate. The AI image generator on img.now runs FLUX models, so you can try it directly in your browser with no software to install.

What FLUX is and why it matters

FLUX refers to a series of diffusion models developed by Black Forest Labs. The most commonly used variants are FLUX.1 Schnell, which generates quickly, and FLUX.1 Dev, which takes a bit longer but tends to produce more detailed results. A third variant, FLUX.1 Pro, is higher quality still and is available through select platforms.

What sets FLUX apart from earlier models is how well it follows instructions. It handles complex scene descriptions without dropping details, and it produces text inside images more reliably than most alternatives. If you have tried other generators and found they ignore half your prompt, FLUX usually does better on that front.

You do not need to understand the model's internals to use it, but knowing that different variants exist helps you set expectations about speed and quality. For background on how these models work in general, see our guide on how AI image generators work.

Writing a prompt for FLUX

FLUX responds well to natural, descriptive language. You do not need special syntax, tokens, or comma-separated tags the way some older systems preferred. Write a clear sentence or two that names the subject, the setting, and the style you want.

A few things to keep in mind:

• Be specific about your subject. "A tabby cat" works better than just "a cat."
• Add lighting and mood. "Soft afternoon light" or "overcast, moody sky" shapes the whole feel.
• Name a visual style if you have one in mind. "Photorealistic," "flat illustration," or "oil painting" all land consistently.
• Keep related ideas together. If the background matters, describe it as part of the scene, not as a separate afterthought.

FLUX handles longer prompts better than many models, so you do not need to cut details aggressively. That said, a prompt with a clear main idea and a few supporting details will almost always beat a long, unfocused list. For more depth on structuring prompts, see our notes on prompt structure.

Choosing your settings

Before you generate, a few settings are worth checking. The most important ones are the model variant, the aspect ratio, and the number of steps.

The aspect ratio matters more than it might seem. A landscape shape changes how a scene is arranged compared to a portrait or square. Pick the ratio that fits where you plan to use the image. Our guide to best AI image aspect ratios maps common shapes to common uses if you are unsure.

Refining your results

Expect to run a prompt two or three times before you land on something you like. This is normal and not a sign the tool is broken.

When a result is close but not quite right, change one element at a time. If the lighting is off, adjust that word. If an unwanted object keeps appearing, describe the scene more specifically so the model has less room to fill in gaps on its own. You can also use negative prompts to steer the model away from things you do not want in the frame.

If the result is mostly good but the composition feels cramped or the subject is cut off, the fix is usually the aspect ratio, not the prompt. Regenerating with a slightly wider or taller frame often solves it without any other changes.

Taking your image further

Once you have an image you like, there are a few common next steps depending on how you plan to use it.

If the resolution feels low for print or large screens, run it through the image upscaler to increase the size without adding blur. If the image has a background you want to remove for a product photo or design asset, use the background remover. If you want to make small color or contrast adjustments, the image enhancer handles that without needing separate software.

Saving your successful prompts is also worth doing. Once you find a prompt structure that works well for a particular style or subject, keeping a note of it saves you from starting from scratch next time.

Checklist

• Write a clear subject, setting, and style in plain language
• Choose the model variant that fits your speed and quality needs
• Set the aspect ratio before generating, not after
• Run the prompt two or three times to compare results
• Change one element at a time when refining
• Use negative prompts if something unwanted keeps appearing
• Upscale or enhance the final image before using it at large sizes
• Save the prompts that worked

Example prompts

These follow the subject, setting, mood, and style pattern that works well with FLUX. Adjust one word at a time to see how the output shifts.

A woman reading a book in a sunlit cafe, warm afternoon light through large windows, calm and focused mood, photorealistic style, portrait frame

An empty cobblestone street in a European city after rain, reflections in puddles, overcast sky, moody and quiet, cinematic wide frame

A close-up of a white ceramic coffee mug on a dark wooden table, steam rising gently, minimal and clean, soft natural light, square frame

FAQ

Does FLUX work better than other AI image generators?

FLUX tends to follow detailed prompts more accurately than older models and handles text-in-image tasks better than most. Whether it is the right choice depends on what you are making, since other models may suit particular styles better.

Do I need an account to use FLUX online?

That depends on the platform. On img.now, you can generate images without creating an account, though accounts let you save your history and settings.

Why does FLUX ignore part of my prompt?

If the model drops a detail, try moving it earlier in the prompt or stating it more directly. Cutting less important words can help the model focus on what matters most. Very long prompts with competing ideas are the most common cause.

What file format does FLUX output?

Most platforms output PNG or JPEG by default. If you need a different format or want to reduce file size for web use, you can convert afterward using the image converter.

Can I use FLUX images commercially?

That depends on the terms of the platform you used to generate them. Check the platform's license terms before publishing or selling. Our guide on using AI images commercially covers the key things to look for.