The upload service is used to upload an image when you want to apply several transformations to it.
By uploading an image first, you'll receive a transaction_id which you can use repeatedly for transformations and thereby avoid having to upload an image for each and every one.
If you're sure you only want to do a single transformation to an image, there's no benefit to using this service. Just jump right to that service.
Limitations: Supported source image formats are JPG, PNG, TIFF and WEBP.
You can source the image by providing a file or a URL to an online image.
Requires an API key to be provided in the X-Picsart-API-Key request header.