Original field_image file binaries are not migrated (display is IIIF)

Area: migration / Images / files Raised during: Sprint 1 (1a.7 — pattern-setting image migration) Jira: (add when available) Priority: Low

Context

The D11 shanti_image display path renders from the existing IIIF server via field_iiif_id (the i3fid), proven in 1a.5. The original uploaded file (field_image) is therefore not on the critical path for display.

Production-data check (2026-06-11 dump): of 111,340 images, only 545 have a field_image file (field_data_field_image.field_image_fid > 0); the other 99.5% have no local file at all and rely entirely on IIIF. The ~36 imageless metadata records (no i3fid and no field_image) are covered separately by the field_iiif_id-optional decision.

Decision (1a.7)

The 1a.7 migration does not migrate the field_image file binaries. It carries field_iiif_id / field_iiif_mms_id / dimensions forward from the shanti_images sidecar, which is what drives display. field_image is left empty on migrated nodes.

This is consistent with ADR 004 (IIIF server stays as-is) and the audit's IIIF-as-wiring stance.

Follow-up (post-MVP, if ever needed)

If those 545 local originals are deemed worth preserving in D11, add a d7_file + field_image migration step (standard Migrate file handling) sourced via field_data_field_image. Low priority — they are a 0.5% tail and not part of the user-facing display path.