The solution I found was creating an AWS API gateway and allowing put requests to an S3 bucket. This was actually quite straightforward and well-documented on youtube. Permissions and roles are a little tricky but doable as a no/low coder and again well documented. However, there was an issue with uploading to a specific bucket and 'folder' which I got some help with. as explained below:
"The problem with trying to create an item in the S3 "input" folder is S3 doesn't really have folders in the underlying bucket, only objects. It simulates a folder in the GUI using the backslash (/) in the key name, but actually all it's doing is creating an object called "input/name.jpg", rather than an object called "name.jpg" in the "input" folder. The other issue is the API gateway uses the same backslash (/) to split a path up. So when you try to put an object with the key including the backslash, the API gateway sees it as a new path, and you get the Missing Token error as that path doesn't exist. It took me a little while to figure out the solution, but the trick is to use the URL encoded form of the backslash in the URL which %2f i.e. "input**/name.jpg" becomes "input%2f**name.jpg".
This allows me to put image attachments to pbposters-images/input using https://my-gateway-my-region.amazonaws.com/prod/pbposters-images/input%2fnew.jpg
So I can now upload directly from any airtable base straight into S3 with the simple script below (created with help from chat GPT):
// Replace 'YOUR_API_GATEWAY_URL' with the URL of your API Gateway endpoint
const apiGatewayUrl = 'https://gateway-region.amazonaws.com/prod/pbposters-images/input%2f';
// Replace 'YOUR_TABLE_NAME' and 'YOUR_FIELD_NAME' with the name of the table and field that contains the image attachment
const table = base.getTable('YOUR_TABLE_NAME');
const record = await input.recordAsync('Process PSDs', table);
const attachment = record.getCellValue('YOUR_FIELD_NAME')[0];
const attachmentName = record.getCellValue('fileName');
const imageUrl = attachment.url;
console.log(imageUrl);
// Download the image data from the URL
const imageData = await remoteFetchAsync(imageUrl, { method: 'GET' }).then(response => response.arrayBuffer());
// Set up the HTTP request options for the PUT method
const options = {
method: 'PUT',
headers: {'Content-Type': 'image/jpeg'},
body: imageData,
};
// Send the image data to the API Gateway endpoint using the PUT method
const response = await remoteFetchAsync(apiGatewayUrl + attachmentName, options);
console.log(response);
