Losslessly optimise png

[petecooper]

Savings of ~50% bytes-wise.

Latest ImageOptim used with lossless settings.

[oracle-contributor-agreement]

Thank you for your pull request and welcome to our community! To contribute, please sign the Oracle Contributor Agreement (OCA).
The following contributors of this PR have not signed the OCA:

• PR author: petecooper
• [email protected] (@petecooper)

To sign the OCA, please create an Oracle account and sign the OCA in Oracle's Contributor Agreement Application.

When signing the OCA, please provide your GitHub username. After signing the OCA and getting an OCA approval from Oracle, this PR will be automatically updated.

If you are an Oracle employee, please make sure that you are a member of the main Oracle GitHub organization, and your membership in this organization is public.

[alan-maguire]

thanks for this! Process requires the OCA is signed before I can merge however.

[petecooper]

OCA signed shortly after PR submission and was stated as pending approval (or words to that effect).

[alan-maguire]

great, thank you! once that gets approved I will merge (should be soon hopefully)

[oracle-contributor-agreement]

Thank you for signing the OCA.