TL;DR recommendation
If you must produce 500 images/month on a budget and want predictable per-image costs with good control over aesthetics, Leonardo AI is generally the more cost‑effective choice. If your priority is top-tier, highly stylized single images and you can tolerate higher per-image cost and more manual iteration, Midjourney may be worth the extra spend.

Decision criteria (use these to pick):
- Budget sensitivity: per-image cost + monthly/API fees
- Quality requirement: photoreal vs stylized/artistic
- Iteration overhead: how many prompts/rounds per final image
- Scale and automation: required API/batch endpoints and rate limits
- Team size and workflow: single designer versus distributed reviewers

Short comparative summary
- Cost structure: Leonardo tends to offer lower per-image and stronger batch/API pricing for production runs (better control-to-price balance). Midjourney historically has higher per-image effective cost when you need lots of fast, high-quality renders and upscales. Check each vendor’s current API credit/pricing page before final decisions.
- Quality trade-offs: Midjourney often wins for distinct, painterly, highly stylized results out of the box. Leonardo is highly controllable, good for consistent renders across a batch and for photoreal/brand-aligned results.
- Iteration and automation: Leonardo’s batch/API features are usually friendlier for automated pipelines; Midjourney has added API capabilities but often still requires more per-image tweaking.

How to compute per-image cost (practical formula)
Total monthly cost = base subscription or platform fee + API/batch fees + (per-image render cost × #images) + (upscale/hi-res cost × #upscales) + human QC labor.
Example (replace numbers from current pricing):
- Base fee: $50/month
- Per-image render: $0.08/image → 500 × $0.08 = $40
- Upscales on 20% winners at $0.20 each → 100 × $0.20 = $20
Total ≈ $110 → effective ~ $0.22/image.
Run the same math for Midjourney with your vendor numbers; compare total and how many iterations you must do per final image.

Workflow checklist to minimize cost (practical)
1. Define specs: final resolution, acceptable style variance, and upscales needed.
2. Prompt template: create and lock a prompt template; store variables for batch substitution.
3. Low-res draft pass: render cheap/small variants in bulk (reduce per-image cost). Cull to top N.
4. Variation pass: only generate variations/upscales on winners.
5. Use API batch endpoints + seeded runs for consistency; script retries and rate-limit handling.
6. QA pass: small human check before upscaling to avoid wasted hi-res costs.
7. Track spend per job; automates alerts at cost thresholds.

Best-for / Avoid-if
- Best-for Leonardo: high-volume deliveries, consistent product shots/brand art, automated pipelines, teams needing lower per-image cost.
- Avoid Leonardo if you need very specific painterly aesthetics where Midjourney’s style is preferred.
- Best-for Midjourney: single high-impact assets, editorial covers, or when creative novelty > unit cost.
- Avoid Midjourney if you need 500+ consistent images with tight per-unit budgets.

When the right answer depends
If your budget is large, or you value Midjourney’s unique style, choose quality over cost. If your team lacks prompt-engineering bandwidth, factor in extra iteration costs. If you have developers, API automation will cut per-image cost substantially.

Practical next steps
1) Pull current API/subscription pricing from each vendor (replace numbers in the formula). 2) Run a 50-image pilot on both platforms (use identical prompts/templates) and record renders, iterations, and total spend. 3) Choose based on per-final-image cost plus QA time.

If you want, I can draft the pilot plan and the exact budgeting spreadsheet for the 50-image test (and run sample prompt templates).

Compare Leonardo AI and Midjourney