Upscale a generated, edited, or existing image

You can use Imagen on Vertex AI's upscaling feature to increase the size of an image without losing quality.

Model versions

Upscaling availability is based on model version:

Feature Imagen (v.002) Imagen 2 (v.005) Imagen 2 (v.006)
Upscaling ✔ Not supported Not supported

Upscale an image

Use the following code samples to upscale an existing, generated, or edited image.

Console

  1. Follow the generate image with text instructions to generate images.

  2. Select the image to upscale.

  3. Click Upscale/export.

  4. Select Upscale images.

  5. Choose a value from the Scale factor (2x or 4x).

  6. Click Export to save the upscaled image.

REST

For more information about imagegeneration model requests, see the imagegeneration model API reference.

Upscaling mode is an optional field in the parameters object of a JSON request body. When you upscale an image using the API, specify "mode": "upscale" and upscaleConfig.

Before using any of the request data, make the following replacements:

  • LOCATION: Your project's region. For example, us-central1, europe-west2, or asia-northeast3. For a list of available regions, see Generative AI on Vertex AI locations.
  • PROJECT_ID: Your Google Cloud project ID.
  • B64_BASE_IMAGE: The base image to edit or upscale. The image must be specified as a base64-encoded byte string. Size limit: 10 MB.
  • IMAGE_SOURCE: The Cloud Storage location of the image you want to edit or upscale. For example: gs://output-bucket/source-photos/photo.png.
  • UPSCALE_FACTOR: Optional. The factor to which the image will be upscaled. If not specified, the upscale factor will be determined from the longer side of the input image and sampleImageSize. Available values: x2 or x4 .

HTTP method and URL: 

POST https://LOCATION-aiplatform.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/publishers/google/models/imagegeneration@002:predict

Request JSON body: 

{
  "instances": [
    {
      "prompt": "",
      "image": {
        // use one of the following to specify the image to upscale
        "bytesBase64Encoded": "B64_BASE_IMAGE"
        "gcsUri": "IMAGE_SOURCE"
        // end of base image input options
      },
    }
  ],
  "parameters": {
    "sampleCount": 1,
    "mode": "upscale",
    "upscaleConfig": {
      "upscaleFactor": "UPSCALE_FACTOR"
    }
  }
}

To send your request, choose one of these options:

curl

Save the request body in a file named request.json, and execute the following command: 

curl -X POST \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://LOCATION-aiplatform.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/publishers/google/models/imagegeneration@002:predict"

PowerShell

Save the request body in a file named request.json, and execute the following command: 

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method POST `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://LOCATION-aiplatform.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/publishers/google/models/imagegeneration@002:predict" | Select-Object -Expand Content

You should receive a JSON response similar to the following:

{
  "predictions": [
    {
      "mimeType": "image/png",
      "bytesBase64Encoded": "iVBOR..[base64-encoded-upscaled-image]...YII="
    }
  ]
}

What's next

Read articles about Imagen and other Generative AI on Vertex AI products: