chore: remove or stop deploying unreferenced top-level images

Problem

Six images at the top level of images/ are referenced by no page, stylesheet, script or index:

• images/IMG_6306.jpg
• images/desk.jpg
• images/harvey.jpg
• images/jack.jpg (not the same file as images/gallery/photographer/portraits/*/jack.jpg, which is used)
• images/lake.jpg
• images/mixing_console.jpg

static.yml copies the whole images/ directory, so they ship on every deploy and get optimised for no reason.

Found by grepping *.html, *.scss, *.css, *.js, *.txt and *.xml for each basename. Spotted during the #131 alt-text sweep.

Proposal

Confirm that none is kept on purpose, for example as a future banner. Then either delete them or strip them in the deploy job alongside images/will/JPEGs/. Related: #102 (deploying from site/).

Acceptance criteria

• Every image under images/ that ships is referenced by a deployed page, or the exception is documented

Recheck references to the six listed files under images/ across the file types named in the issue, then inspect static.yml and the existing images/will/JPEGs/ deploy handling. Confirm whether any image is intentionally retained, choose the issue's deletion or deploy-stripping path, and verify that every shipped image is referenced or documented as an exception.