# preview_screenshot (https://lazyfrog.dev/docs/tools/preview_screenshot)

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**{"Screenshot"}** · Reads only

<p>{"A screenshot of a page of the project's running app (path, viewport desktop, mobile, tablet, wide or all, or width: any width in px, full_page). A path with a fragment (\"/#rooms\") shows that part of the page; full_page scrolls through first, so lazy pictures are in. viewport all returns phone, tablet and wide laptop side by side in one image: use it to see a layout at every width in one call. Returns the image and a link to it that works for an hour. Use it to see what you built; design_check also measures what to fix. Pages behind the app's own sign-in: sign in with http_request, then pass its session cookie as headers {\"Cookie\": \"...\"} (sent only to the app; the log keeps header names only). The page's own WebSockets reach the app (a dev server's live reload, a live view's updates); sockets to other sites are closed. It also lists the browser errors in that clean browser (no extensions): uncaught errors, console errors and the app's own failed requests (include_warnings adds console warnings), or says none; when the user reports an error from their own browser, look here first. When the page didn't answer 2xx (a missing page's 404, a 500), its first line says so. compare: true compares with the previous screenshot of the same page, viewport and env: how alike, which parts changed and which didn't (the header, each section, the footer); take one before a change and one with compare after it, since an edit that succeeded isn't proof it looks right. reference: an image under data/import of how it should look (the person's upload, a captured site's screenshot): how alike the page is and where it differs most."}</p>