docs: add initial documentation for Getty Images data source

[Geethanjali2412-K]

Fixes

• Related to Add Getty images as data source #248 by @oree-xx

Description

This pull request adds documentation for Getty Images as a potential data
source for the Quantifying the Commons project.

The documentation explains a proposed Getty Images API query and describes the
type of data that would be produced, using clear, high-level explanations rather
than raw API responses or media files.

Technical details

The Getty Images API (v3) provides access to metadata for a large collection of
commercial visual content, including images, illustrations, videos, and
editorial media from Getty Images and iStock.

The API returns metadata only and does not require downloading or storing media
assets. Requests are authenticated using an API key and responses are returned
in JSON format.

A representative API query could:

• Search for image assets using a keyword or subject term (for example,
  “education”)
• Filter results by asset type (images only)
• Request metadata related to contributors and licensing

If the results of this query were stored as a dataset, the resulting data file
could include the following headers:

• asset_id
• asset_type
• title
• description
• creator_name
• collection_name
• license_model
• usage_restrictions
• keywords
• created_date

This structure enables analysis of licensed creative works without downloading
or storing the underlying media files.

Checklist

• I have read and understood the Developer Certificate of Origin (DCO), below, which covers the contents of this pull request (PR).
• My pull request doesn't include code or content generated with AI (also see Avoiding generative AI development tools — Creative Commons Open Source).
• My pull request has a descriptive title (not a vague title like Update index.md).
• My pull request targets the default branch of the repository (main or master).
• My commit messages follow best practices.
• My code follows the established code style of the repository.
• I added or updated unit tests and/or test scripts for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no
  visible errors.

Developer Certificate of Origin

For the purposes of this DCO, "license" is equivalent to "license or public domain dedication," and "open source license" is equivalent to "open content license or public domain dedication."

Developer Certificate of Origin

Developer Certificate of Origin
Version 1.1

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Developer's Certificate of Origin 1.1

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(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
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(b) The contribution is based upon previous work that, to the best
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[TimidRobot]

Pull requests (PRs) that don't use the description template can't be accepted. Please update the description.

Instead of creating a new file, please add a section to sources.md. The existing entries give examples regarding what has been found to be most helpful.

It would also be helpful to document specific API usage/queries in the description of this PR.

[Geethanjali2412-K]

Thank you for the feedback, that’s very helpful.

I’ll update the PR description to use the required template and move the
documentation into sources.md as suggested. I’ll also add more detail
about the specific API queries and usage in the PR description.

I’ll push the updates shortly.

[Geethanjali2412-K]

I’ve updated the PR to use the required template, moved the documentation into
sources.md, and added example API usage to the PR description.
Please let me know if anything else should be adjusted.

[TimidRobot]

I’ve updated the PR to use the required template, moved the documentation into sources.md, and added example API usage to the PR description. Please let me know if anything else should be adjusted.

Please update the PR description with the proposed API query and what the headers would be for the resulting data file(s).

[TimidRobot]

Pull requests (PRs) that don't use the description template can't be accepted. Please update the description.

@Geethanjali2412-K This has not yet been completed.

[Geethanjali2412-K]

Hello.. I’ve updated the PR description to fully follow the required template.
Let me know if you have any changes required.