External IIIF images should only need `src` or `printImage`, not both

[geealbers]

Before proceeding, make sure there isn’t an existing issue for this bug.

• I have searched the existing issues and determined this is a new bug.

Expected Behavior

When including an external IIIF image with manifestId and canvasId, users should only have to specify a single static image to be used where zooming tiles wouldn't be:

- id: "irises"    
  manifestId: https://media.getty.edu/iiif/manifest/53be857e-41e8-4198-b45d-2e0f52d3051b
  canvasId: https://media.getty.edu/iiif/manifest/canvas/e5d29650-11f8-4897-9540-54a9dd65b04f.json
  src: figures/irises.jpg

Actual Behavior

Instead, users have to include both a src and a printImage:

- id: "irises"    
  manifestId: https://media.getty.edu/iiif/manifest/53be857e-41e8-4198-b45d-2e0f52d3051b
  canvasId: https://media.getty.edu/iiif/manifest/canvas/e5d29650-11f8-4897-9540-54a9dd65b04f.json
  printImage: figures/irises.jpg
  src: figures/irises.jpg 

The src is used in the the table-of-contents grid (in all outputs), but a printImage also needs to be defined to display in the PDF and EPUB as inline figures. Further, without the src also being defined, printImage will not display in the PDF and EPUB, even if printImage is defined.

Steps to Reproduce

1. Start a new project
2. Add an external IIIF figure, but with only printImage or src defined
3. Use that figure on an entry page lightbox, on a page with the figure shortcode, and in a table of contents page with presentation: grid
4. Build the various outputs and check to see where the figure is or is not included

Version Numbers

[test-latest-41]
 quire-cli 1.0.0-rc.33
 quire-11ty 1.0.0-rc.41
 starter https://github.com/thegetty/quire-starter-default@2.10.0
[System]
 quire-cli 1.0.0-rc.33
 node v22.10.0
 npm 10.9.0
 os Darwin 22.6.0

Web Browser

No response

Relevant Terminal/Shell Output

Supporting Information

This issue was originally opened in Jira by @geealbers on 22/Aug/23 as DEV-15826, DEV-15827, and DEV-15828.