copy_adapt

A: Light divergence / “fork + extension” What stays similar

Use the same or a closely similar UI paradigm (gallery, lightbox, swipe) so users familiar with PhotoSwipe feel comfortable.

Keep API / method names somewhat analogous (e.g. similar function signatures, plugin structure) so migrating is easy.

Reference “built on PhotoSwipe” or “extension of PhotoSwipe” somewhere (disclosure, lineage).

Use some shared semantic structure or directory structure that mirrors their docs (but not verbatim).

What changes / differentiates

New brand name / domain (not photoswipe.com or anything too close).

Completely rewritten marketing copy, documentation, tutorial examples, case studies.

Your AI / SEO module features clearly surfaced (e.g. “Auto Alt AI,” “Gallery SEO Score,” “Metadata Suggestion”) — these should be front & center differences.

Unique visual branding (logos, color scheme, icons).

Different package naming / module names (so users don’t import “photoswipe” inadvertently).

Possibly different folder / module structure so your version has modular “AI plugin” layers as distinct.

Pros

You benefit from familiarity / low friction for users who know PhotoSwipe.

Users see similarity but recognize your added value (AI / SEO) — ease of switching / testing.

Lower cognitive load for adoption, since users see “it looks like what they expect.”

Some SEO overlap / relevance — since users searching for "PhotoSwipe plugin" might see your extension.

Cons / risks

If your marketing or copy is too close, search engines may see you as duplicate / derivative and suppress your pages relative to the original.

Users might perceive you as just a “tweak / fork,” which reduces your distinct brand identity.

It may be harder to defend or stand out, especially if a competitor clones your AI/SEO layer too.

Traffic / SEO risk

Moderate. You have a chance to “steal” some tail traffic from people searching “PhotoSwipe plugin X” or “PhotoSwipe AI”, but many of the head terms will still favor the original domain’s authority.

You run the risk that your domain is filtered or outranked if your content is too close.