Quick answer
Use one consistent Midjourney base-template (a blank product PNG or a studio mockup image) + a single stable prompt skeleton that you fill with each SKU’s design name. Batch /imagine calls from a spreadsheet or automation, upscale consistently, then run a single background-removal + resize pass to produce Shopify-ready files.

Recommendation (what to run)
- Create a blank high‑quality product template image (transparent PNG) for the mockup (shirt, box, mug, etc.).
- Use Midjourney in Discord or API with a single prompt template (example below). Keep aspect ratio, lighting, lens, and stylize fixed so all 50 images match.
- Upscale each chosen result in Midjourney or an external upscaler to your target px, then batch remove backgrounds and convert to sRGB JPG/PNG for Shopify.

Concrete prompt template (replace {{DESIGN}} and use the same template image uploaded to MJ)
" photorealistic mockup of a product with printed design: '{{DESIGN}}', clean studio, softbox lighting, shallow depth of field, 85mm, high detail, neutral white background, true-to-life color, product centered, minimal shadows --ar 1:1 --v 6 --stylize 50 --quality 2"
Notes: use --ar 1:1 for square Shopify images. If you prefer vertical use 4:5. Keep --stylize low (20–60) for photoreal consistency.

Batching workflow (50 SKUs)
1) Prep: collect 50 design names/files in a CSV: SKU, design_text, design_image_url (if you use image prompts). Upload one consistent blank product PNG to Midjourney and use that image URL in the prompt.
2) Generate: use the spreadsheet to programmatically create 50 /imagine messages (Discord bot, Midjourney API, or manual copy/paste). Use the same prompt skeleton, swapping only the {{DESIGN}} field.
3) Choose/Variants: for each /imagine, pick the variant you like and click Upscale (U1–U4) or use the MJ upscaler to get larger resolution.
4) Batch background removal: run all upscaled images through a batch remover (remove.bg, Photoshop action, or another background-removal API). Convert to transparent or white background per your store style.
5) Resize & color profile: export to sRGB JPEG at 2048x2048 (Shopify recommended primary size). Also create 800x800 or 1024x1024 thumbs.
6) Final QA & naming: check colors, shadows, and reflections; name files SKU_main.jpg, SKU_thumb.jpg.

Decision criteria (pick options)
- Budget: use Midjourney + remove.bg (paid) for fastest route. If on a tight budget, generate lower-res and use free remove.bg quota or free Photoshop tools.
- Skill level: non-technical—manual Discord + remove.bg web UI. Tech-savvy—automate with the Midjourney API + background-removal API.
- Output quality: need studio-realistic product photos? Keep stylize low, use photo descriptors and upscaling.

Best-for / Avoid-if
- Best-for: stores needing consistent, fast mockups across many SKUs, designers who can prepare one template.
- Avoid-if: you need exact brand-accurate fabric folds or prints—those require photography or a 3D mockup pipeline.

Practical checklist
- [ ] Create/upload blank product PNG
- [ ] Finalize prompt skeleton and settings (--ar, --v, --stylize)
- [ ] Create CSV with 50 design prompts
- [ ] Run batch /imagine (Discord/API)
- [ ] Upscale chosen images
- [ ] Batch background removal and convert to sRGB
- [ ] Resize to Shopify sizes, QA colors, name files

If you want, I can convert the prompt into a ready CSV template and a short Discord/automation script sketch using the Midjourney API to run the 50 prompts.

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