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Compare Image Scraping Sessions — Bulk Image Downloader Pro

danito
Compare Image Scraping Sessions — Bulk Image Downloader Pro

When you scrape the same source more than once, the hard question is not always ?what did this page contain?? It is ?what changed since last time?? If you save snapshots of scraper results, you can compare image scraping sessions instead of manually checking two long URL lists.

Bulk Image Downloader Pro includes session comparison in the side panel for saved scraper sessions.

What session comparison shows

The comparison tool takes two saved sessions and compares their image URL sets. It shows the size of each session, the number of URLs common to both, and URLs unique to each session.

This is useful when a gallery, product page, board, archive, or supplier page changes over time.

Use it to find new or missing images

If session A is last week’s scrape and session B is today’s scrape, URLs unique to the newer session are likely new discoveries. URLs unique to the older session may be images that disappeared, moved, or were no longer found by the scanner.

The comparison does not explain why a URL changed. It gives you the difference so you know where to inspect next.

Comparison is URL-based

Session comparison works from saved result URLs. It does not perform visual matching, perceptual duplicate detection, or content recognition. If the same image appears at two different URLs, the comparison treats those as different URLs.

For visual duplicate checks, use the separate duplicate finder workflow outside the side-panel session comparison.

When comparison is useful

Use comparison for recurring sources: ecommerce listings, competitor galleries, research boards, content migration checks, and image-heavy pages that update over time.

It is also useful for confirming whether a new scan added anything worth downloading before you create another task.

A practical comparison workflow

  1. Save a session after the first useful scrape.
  2. Scrape the same or related source later and save another session.
  3. Open Compare Sessions and choose the two saved sessions.
  4. Review common URLs and URLs unique to each session.
  5. Use the unique newer URLs to decide what needs attention.
  6. Save or export important session records when you need an audit trail.

For preserving a result set first, read save image scraping sessions. For repeat source setup, see save image scraping rules for websites.