There is no way to do this currently. Internally we track which blobs we have processed by storing receipts in our control container azure-webjobs-hosts. Any blob not having a receipt, or an old receipt (based on blob ETag) will be processed (or reprocessed). That's why your existing blobs are being processed - they don't have receipts. BlobTrigger is currently designed to ensure that ALL blobs in a container matching the path pattern are eventually processed, and reprocessed any time they are updated.
If you feel passionately about this, you can log a feature request in our repo here with details on your scenario.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
