A. Upload files to an OCI Object storage bucket. Every time a file is uploaded, an event is emitted. Write a rule to filter these events with an action to trigger a function in Oracle Functions. The function processes the image in the file and stores the thumbnails back in an Object storage bucket.

B. Upload files to an OCI Object storage bucket. Every time a file is uploaded, trigger an event with an action to provision a compute instance with a cloud-init script to access the file, process it and store it back in an Object storage bucket. Terminate the instance using Autoscaling policy after the processing is finished.

C. Build a web application to ingest the files and save them to a NoSQL Database. Configure OCI Events service to trigger a notification using Oracle Notification Service (ONS). ONS invokes a custom application to process the image files to generate thumbnails. Store thumbnails in a NoSQL Database table.

D. Upload all files to an Oracle Streaming Service (OSS) stream. Set up a cron job to invoke a function in Oracle Functions to fetch data from the stream. Invoke another function to process the image files and generate thumbnails. Store thumbnails in another OSS stream.