Known limits
Honest boundaries beat a fake success message.
Browsers and websites enforce real security boundaries. ImageSave explains the supported path, offers a labelled fallback where it can, and refuses work that cannot be completed safely.
Some pages are off limits
Chrome's own pages, the Chrome Web Store, inaccessible frames, closed shadow roots, protected media, and some browser-controlled surfaces cannot be scanned or modified by an extension.
A visible image may not expose a reusable source
Expired blob URLs, tainted canvas, authenticated application requests, DRM, and site security controls can block direct access. A labelled Visible Pixels capture may be offered where supported, but it is not claimed as Original.
Discovery is deliberately bounded
A scan admits at most 2,000 candidates and prioritizes ordinary image, canvas, video-poster, and inline-SVG media while preserving room for CSS and pseudo-element sources. It does not promise to exhaust every URL a page could produce.
Best Copy follows page declarations
It can group responsive sources declared by one element. It does not perform visual matching or guarantee that a larger URL is the creator's original file.
Static output is intentionally static
Saving Original can preserve an animated source. PNG, JPG, WebP, static GIF, BMP, or ICO output requires a specific still frame when the source is animated. Multi-frame conversion is not supported.
Not every image format is an output
There is no TIFF or AVIF encoder. ImageSave does not turn raster pixels into vector SVG. GIF output is one frame with at most 256 colors and binary alpha; ICO is one square PNG-backed entry up to 256 × 256.
Original has a narrower guarantee
For normal HTTP(S), Original means the server-provided file Chrome downloads. Because it streams through Chrome, ImageSave does not claim a verified pre-save byte count, dimensions, or MIME type for that download.
Only generated previews can be exact before save
Exact generated PNG, JPG, and WebP size calculation creates one retained asset for preview and save. That asset expires after two minutes and must then be prepared again.
Watch limits
Watch runs only after you start it. It does not auto-scroll, click controls, invent URLs, or refetch assets. It stops when you stop it, leave the session, navigate, hit an error, or reach a hard limit: five minutes, 10,000 events, 50,000 examined nodes, 500 milliseconds of scanner CPU, or 2,000 candidates.
Batch and memory limits
A generated ZIP entry is capped at 24 MiB and the nominal archive cap is 48 MiB. Under the conservative 96 MiB peak model, an all-generated archive is effectively capped at 32 MiB. Retained output also counts toward the 256 MiB transform cap. Over-limit work is refused or moved to the explained separate-save path; it is not silently dropped, resized, or relabelled.
Rights and site controls
ImageSave does not bypass DRM, authentication, paywalls, browser security boundaries, or site access controls. Save only images you have the right to use. If a failure does not match these boundaries, see support.