Building Image Generation into Apps

Architecture

User prompt ──▶ Flask endpoint ──▶ image API (or your GPU server)
                     │                       │
                     ▼                       ▼
              moderation, limits       image URL / bytes
                     │
                     ▼
              object storage + database record ──▶ user gallery

Server-side only

Keep API keys on the server. The endpoint should:

• require login and apply per-user rate limits and quotas,
• validate and moderate prompts (and generated images, where tools provide moderation),
• run generation in a background job and notify the user (images can take many seconds),
• store results in object storage (S3/R2) with a database record of prompt, model, settings and user,
• serve images through signed or permission-checked URLs if they are private.

Costs

Image generation is priced per image (by size and quality) or by GPU time. Track cost per user, set quotas per plan, and cache or reuse results where possible.

User experience

• Show progress and an estimated wait.
• Offer prompt helpers (style presets, aspect ratio buttons) so users get good results without prompt expertise.
• Provide variations, simple edits and downloads.
• Make it clear the images are AI-generated and what users may do with them under your terms.

Safety

Block requests for sexual content involving minors (absolutely), non-consensual intimate imagery, realistic depictions of real people in misleading situations and other harmful content, using both provider moderation and your own rules. Log moderation decisions and provide a way to report abuse.

Final project

Build an "AI product scene" feature: users upload a product photo, choose a scene preset, and receive four generated lifestyle images composited around the real product. Include login, quotas, background jobs, object storage, moderation, a gallery and cost tracking per user.

Check yourself

• Why run generation in a background job?
• What should be stored with each generated image?
• Which content must always be blocked?