Could you provide more details of the API calls you were making? Generally the error:

{"id":"not_found","message":"The resource you were accessing could not be found."}

is only returned if you are trying to access an endpoint that does not exist. It’s likely there is a typo in the URL. For most image related problems, you get a more specific error message.

If the image doesn’t exist, you get:

{"id":"unprocessable_entity","message":"You specified an invalid image for Droplet creation."}

If it’s not available in the region you are trying to launch it in, you get:

{"id":"unprocessable_entity","message":"The image you specified is not available in the selected region, you can transfer it to this region from the images pages."}