gpui: Make `image` example work regardless of how it is run (#24645)

This PR updates the GPUI `image` example such that it works when run in
the following ways:

- `cargo run -p gpui --example image` from the repository root
- `cargo run --example image` from within `crates/gpui`

Release Notes:

- N/A
04d65cb3cdMarshall Bowers committed on 2/11/2025, 1:34:38 PM· committed by GitHubparent6a40a40
3 files changedLine totals unavailable