fix(nodes) paste_image paste mask transparency and img_scale add multiple of

[Neosettler]

Summary

fix(nodes): paste_image, paste mask operation doesn't want a black backdrop. Black should translate to transparent and the hack here is to used the reference image instead. Thus, acting as transparent but it's technically not. + img_scale, add "multiple of" for convenience

Related Issues / Discussions

QA Instructions

Merge Plan

Checklist

• [ ] The PR has a short but descriptive title, suitable for a changelog
• [ ] Tests added / updated (if applicable)
• [ ] Documentation added / updated (if applicable)
• [ ] Updated What's New copy (if doing a release after this PR)

[Neosettler]

expected before and after result: