Free and Pro model usage includes a set number of image requests, and different actions use them at different rates:
Generating a single image: 1 request
Generating 2, 3, or 4 variants: 1 request per image
Editing an image: 2 requests
Multi-image editing: 4 requests
2x Upscale (with enhance): up to 8 requests
4x Upscale (with enhance): up to 16 requests
2x Upscale (without enhance): up to 10 requests
4x Upscale (without enhance): up to 20 requests
You can mix these actions until your included image requests are used up. Limits reset based on your first request in each rate-limit period. Pay-per-use models are separate and are not limited by the image requests included in your plan.