ReadonlydetailWhat the HTTP client reported, for a person to read.
ReadonlyfailureWhat went wrong, for a program to branch on rather than match a message.
'status' carries the HTTP code in ImageWarning.status; the rest
describe a fetch that never produced a response to have a code.
ReadonlynodesHow many nodes in this render named this source.
Deduplicated by URL, with the count beside it. One dead URL asked for three times is one thing that went wrong; three identical entries would be noise. The URL is what locates a defect — it is the only thing separating "the art is not uploaded yet" from "this path has never been right", and a consumer cannot recover it after the fact — and the count says how much of the page it cost.
Optional ReadonlystatusThe HTTP status, when ImageWarning.failure is 'status'.
ReadonlyurlThe URL that could not be resolved.
One image source that could not be resolved, and what the render did about it.
A render that finishes with warnings is not one that succeeded quietly. Every entry is a picture the caller asked for and did not get; the render completed because failing a whole card for one decorative icon is worse for a server drawing from somebody else's payload, not because the failure stopped mattering.