Image to image

Send input images with a generation to edit or reference them. Input roles, which models accept them, uploading local files, and what inputs cost.

An edit is the same POST /image/generate as a text prompt, plus inputs. Pass a model whose catalog entry lists img->img, and check its inputs.rules for how many images it takes.

import Mynth from "@mynthio/sdk";

const mynth = new Mynth();

const task = await mynth.image.generate({
  model: "black-forest-labs/flux.2-pro",
  prompt: "The same lighthouse, now in heavy fog",
  inputs: ["https://cdn.example.com/lighthouse.png"],
});

Inputs and roles

inputs takes up to 20 entries. A string is a public image URL. The object form sets a role:

{
  "type": "image",
  "as": "reference",
  "source": { "type": "url", "url": "https://cdn.example.com/lighthouse.png" }
}

`as`	Meaning
`source`	The image to edit
`reference`	An image to take style or content from
`auto`	Let Mynth assign a role the model accepts. The default

The catalog entry's inputs.rules says which roles the model has and how many images each allows. A rule with no kind accepts any image. In the CLI, set a role with a prefix: -i source:./photo.png or -i reference:https://....

An input URL must be reachable from the public internet. An image Mynth cannot fetch or read fails with invalid_input.

Pass a model that edits

With an explicit model, inputs are checked when the task is created. A model that cannot take them, or too many of them, answers 400 validation_error and nothing is queued.

auto does not look at inputs. An edit sent with auto can be accepted and then fail with capability_not_supported when it lands on a model that cannot edit. The model field has the details.

Local files

The SDK and the CLI upload local files for you. In the SDK, put a File or Blob in inputs. In the CLI, pass a path to -i.

const task = await mynth.image.generate({
  model: "black-forest-labs/flux.2-pro",
  prompt: "The same lighthouse, at noon",
  inputs: [file],
});

Over REST, upload first with POST /image/upload and pass the returned URLs:

curl https://api.mynth.io/image/upload \
  -H "Authorization: Bearer $MYNTH_API_KEY" \
  -F "images=@./lighthouse.png"

{ "data": { "urls": ["https://cdn.mynth.io/inputs/img_3f9a0c1d2e4b5a6978c0d1e2f3a4b5c6.png"] } }

An upload takes up to 10 JPEG, PNG, or WEBP files, each between 1 KB and 10 MB. It is free, and the URLs are served for 1 day. The SDK and the CLI send all local files of one request in a single upload, so the same 10-file limit applies to them.

Price

Models that charge for inputs list per_input in the catalog. It is charged once per input image for each successful output, so two inputs at count: 4 add eight input charges to the four image charges. A model without per_input charges nothing for inputs. Pricing has the formula.

Next steps

Generate images: the rest of the request.
Choosing an image model: finding a model that edits.
Remove background: a cutout without a prompt.

import Mynth from "@mynthio/sdk"; const mynth = new Mynth(); const task = await mynth.image.generate({ model: "black-forest-labs/flux.2-pro", prompt: "The same lighthouse, now in heavy fog", inputs: ["https://cdn.example.com/lighthouse.png"], });