Midjourney v6 vs Grok 2 (Flux) for Mobile App Icon Design: Which Generator Actually Outputs Centred, Scalable UI Assets?

Designing a mobile app icon is an exercise in extreme restraint. You have a tiny square canvas to convey a brand's entire identity, meaning every pixel, shadow, and geometric line must work in perfect harmony.

We have spent hours watching progress bars tick up to 100% on image generators, trying to get a perfectly centred, mathematically balanced icon that doesn’t require three hours of manual path repair in vector software. Historically, AI image generators have struggled with this. They love organic chaos; they hate rigid grids.

With the release of Midjourney v6 and xAI's Grok 2 (which is powered by Black Forest Labs’ Flux engine), we finally have two image generators capable of high-fidelity, professional-grade output. But which one actually understands the strict rules of UI and icon design?

Let’s put them through their paces across two distinct design styles: a minimalist, flat vector icon and a complex, glossy 3D game icon. If you want to check how to wire these assets into interactive prototypes later, take a look at our guide on /platforms/figma-weave.

The Brief: What Makes a Great App Icon?

To keep our test fair, we judged both models on three strict design criteria: 1. Geometric Centring: Is the main subject perfectly dead-centre, or does it lean awkwardly to one side, requiring manual crop-and-fill work? 2. Symmetry and Contrast: Are the curves clean, the straight lines actually straight, and the contrast sharp enough to look good at 16x16 pixels? 3. Prompt Adherence and Text: If we ask for a specific letter mark or clean flat vector style, does the model deliver, or does it try to insert weird, unprompted airbrushing?

Midjourney v6: High Art with High Friction

To run our Midjourney tests, we used their web interface. If you need help getting started or setting up your generation parameters, check out our guide at /platforms/midjourney/articles.

The Flat Vector Test We started with a clean, modern prompt: `A flat vector mobile app icon of a minimalist geometric owl, solid background, high contrast, material design, SVG style --no shadows, 3d, realistic --v 6.0`

• The Result: Midjourney produced an incredibly beautiful, highly artistic owl. The colour palette was stunning. However, it completely ignored our --no shadows parameter, adding a subtle gradient shadow behind the owl's head.
• The Big Issue: The owl was off-centre by about 12 pixels to the left. For a UI designer, this is incredibly frustrating. To use this icon, you have to bring it into an editor, mask the subject, manually centre it, and patch the background colour.

The 3D Glossy Game Icon Test We switched gears to a classic 3D game asset: `A 3D glossy app icon for a mobile puzzle game, featuring a shiny golden key floating on a deep blue background, isometric angle, rich lighting, claymation style, high detail --v 6.0`

• The Result: This is where Midjourney absolutely shines. The reflection of the light on the golden key was breathtaking. It managed depth, subsurface scattering (making the key look genuinely tangible), and a rich, cinematic atmosphere that felt production-ready out of the box. You can see similar stunning examples of this aesthetic in Midjourney's official showcase gallery.

Read more about Midjourney’s capabilities and licensing details on our /platforms/midjourney.

Grok 2 (Flux): Symmetrical Precision and Text That Works

For our Grok 2 tests, we used the "Super Model" setting, which utilises the full capabilities of the Flux.1 engine. If you are having trouble scaling your generations via API, take a look at /platforms/grok/articles.

The Flat Vector Test We ran the exact same geometric owl prompt inside Grok 2.

• The Result: The difference was night and day. Grok 2 delivered a truly flat, perfectly symmetrical vector style owl. There were no unwanted drop shadows, no weird gradients, and—most importantly—the icon was perfectly centred on the canvas.
• Vector Readiness: Because the lines were so clean and the background was a perfectly uniform flat colour, running this output through an automated vectoriser (like Illustrator's Image Trace) yielded a nearly perfect SVG in a single click. No manual node cleanup required.

The 3D Glossy Game Icon Test Using our isometric golden key prompt, we let Grok 2 run.

• The Result: Grok’s interpretation was extremely clean and mathematically precise. The key was perfectly isometric, and the proportions were immaculate. However, it lacked the "soul" of Midjourney's render. The lighting felt a bit flat, looking more like a standard CAD render than a stylized, engaging mobile game icon. It was technically perfect, but aesthetically sterile.

Check out our detailed breakdown of Grok's underlying engine capabilities on /platforms/grok.

The Grid Test: Which Generator Actually Centres Your Subject?

To prove our point about alignment, we ran a test generating a simple letter "M" on a circular badge.

• Midjourney v6 generated gorgeous, ornate typography, but the letter was rarely perfectly upright, and the circle surrounding it was often slightly egg-shaped. It treats every image as a painting, not a technical asset.
• Grok 2 (Flux) produced a mathematically perfect circle with a crisp, upright, perfectly centred "M" in the exact font style requested. For UI elements, buttons, and system icons, Grok's spatial awareness is vastly superior.

Exporting and Vectorising: Post-Processing Workflows

Regardless of which tool you use, you will need to process these assets before they hit an app store. Here is our recommended workflow: 1. Generate high-res: Generate at a 1:1 aspect ratio. If using Midjourney, use the U1-U4 upscale buttons to maximise resolution. 2. Upscale and Clean: If using Midjourney, you will likely need to use an external editor to crop and re-centre the subject. Grok's outputs can usually be exported directly. 3. Vectorise or Export as PNG: For 3D icons, export as a high-resolution PNG, then use tools like Figma to apply the standard iOS or Android squircle masks. For flat icons, use an AI vectoriser to convert the output into paths.

Pricing, Licensing, and Generation Limits

Before choosing which tool to commit to for your workflow, consider the financial and platform constraints:

• Midjourney v6: Starts at $10/month. The basic plan gives you limited fast generations, while higher tiers ($30+) offer unlimited relaxed generations. Note that Midjourney owns the assets unless you are on a plan that explicitly grants commercial usage, and your generations are public by default unless you pay for the Pro plan's Stealth Mode.
• Grok 2 (via X Premium): Included with X Premium/Premium+ subscriptions (starting at around $8/month). It offers incredibly fast generation times with relatively high daily limits, and your generations are private by default.

The Verdict: Which Tool Belongs in Your Design Stack?

For mobile app icon design, the winner depends entirely on your target art style:

• Choose Grok 2 (Flux) if you are designing flat, minimalist, geometric, or typography-heavy icons. Its spatial accuracy, ability to render text, and clean lines will save you hours of vector cleanup work.
• Choose Midjourney v6 if you are designing rich, textured, 3D, or highly illustrative icons (especially for games). It may require a bit of manual cropping and alignment in post-production, but its sheer artistic rendering of light, material, and atmosphere remains unmatched.