https://www.xnview.com/en/png-viewer/
PNG Viewer — Open .png and Animated PNG (APNG) Free with XnView
XnView is a free PNG viewer for Windows, macOS and Linux. Open, edit and batch convert PNG and animated PNG (APNG) images with full transparency support.
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https://heic.best/
Free HEIC Converter Online – JPG, PNG, PDF & Viewer
Free online HEIC converter. Convert HEIC to JPG on Mac, iPhone, or Windows, plus HEIC to PNG and convert HEIC to PDF. Batch-friendly, no install.
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