Update serve-from-custom-domains.mdx

[OnCloud125252]

Summary

Edited Document:
Products > Cloudflare Images > Upload images > Upload via custom path

Enhance Transform Rules Guide with More Flexible Path Matching

• Add option for flexible path matching in Transform Rules setup.
• Include conditional logic to handle requests from specific hostnames.
• Update instructions to reflect changes in regular expression and path handling.
• Ensure clarity in steps for entering dynamic rewrite paths.

Documentation checklist

• The documentation style guide has been adhered to.
• If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• Files which have changed name or location have been allocated redirects.