[CI] Automate Image Compression via GitHub Actions

[aniruddhaadak80]

Problem

Large uncompressed images are frequently merged into the repository, negatively impacting the repository size, cloning time, and website loading speed for end-users. There is no automated check to ensure images are appropriately compressed prior to merging.

Proposed Changes

• Introduce an automated CI check that requires all new or modified images to be compressed.
• Fail the CI pipeline if uncompressed or overly large images are detected in a PR.
• Provide contributors with clear feedback on how to compress their images.

[eduardo-rodrigues]

See motivation to close in the related PR.