Apps similar to Preview include SumatraPDF, which is free and open source. Other options are Okular, IrfanView, XnView MP and ImageGlass. You're spoiled for choice with Image Viewers like Preview: we list more than 100 alternatives for Windows, Mac, Linux, Android and iPhone.
MakeACopy is an open-source document scanner app for Android that allows you to digitize paper documents with OCR functionality. The app is designed to be privacy-friendly, working completely offline without any cloud connection or tracking.
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PicView is a fast, free and fully customizable picture viewer for macOS and Windows 10/11. It supports virtually all image file types, including (animated) WEBP, (animated) GIF, SVG, AVIF, HEIC, PSD and many others.
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Lightweight Simple Image Viewer with Slide show feature, Resize and Lossless-cut, Color correction, Rename, Multi-language and more...
PDF Viewer (aka pdf.js) is a new revolutionary extension using web standard technologies that allows you to display within Mozilla Firefox almost all PDF files found on the web without a plugin.
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High-performance viewer for documents and images offering split tabs, customizable single or book layouts, portals for side-by-side sections, instant search, line highlight, annotation tools, link hints, searchable highlights, session management, and TOML config.
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Qt5 image viewer with optional video support. Ability to quickly copy / move images to different folders. Can open some extra formats (JPEG-XL, AVIF, APNG, HEIF/HEIC, RAW) via third-party image plugins.
MS Paint for the Mac. Native, free and open source: blank canvas at any size, drop one image onto another, crop, and mark up screenshots.
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PDF viewer for macOS supports scientific papers, annotations, highlights, bookmarks, split view, exporting notes, AppleScript, multiple annotation types, bibliography integration, full-screen, search, and compatibility with various macOS versions.
Read, annotate, and highlight PDFs, fill interactive forms with saved input, underline or strike through text, manage bookmarks, sync files from cloud services, and share documents. Compatible with Preview and Adobe Acrobat annotations, supporting extensive iOS features.
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gThumb is an image viewer and browser for the GNOME Desktop. It also includes an importer tool for transferring photos from cameras.
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Create, Convert, Review and Edit PDF Documents on Windows, macOS, and Linux.
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Fly Photos is one of the fastest photo viewers built for Windows, designed as a modern replacement for the now-discontinued Google Picasa Photo Viewer.
