Fast Image Browser Pro

A lightweight Linux alternative to FastStone Image Viewer for dual-tree thumbnail browsing, 2-up/4-up side-by-side photo comparison, magnifier loupe inspection, red-eye/retouch tools, and framed slideshow/contact-sheet export. Disclaimer: Independent open-source project, not affiliated with or endorsed by FastStone Soft.

KEY FEATURES:
• Directory Tree, Thumbnail Browser & 3x Magnifier Loupe: Scan real Linux folders (/usr/share/pixmaps, /usr/share/icons/hicolor, user home, or custom directories), inspect image dimensions, color depth, aspect ratio, live 3x pixel magnifier loupe, and 256-bin RGB histogram, plus quick pixel retouch tools (Crop Board, Drop Shadow Frame, Red-Eye / Spot Desaturate, Auto Levels, Sepia / Warm Tone, Rotate / Flip).
• 2-Up / 4-Up Side-by-Side Comparison & Pixel Diff Inspector: Synchronized zoom/pan comparison panels with real computed Pixel Difference Heatmap, exact MSE, PSNR (dB), windowed SSIM approximation, 64-bit Hamming dHash distance, byte-size delta, and 1-click comparison sheet PNG export.
• RIFF MJPEG Crossfade Slideshow (.avi) & Contact Sheet Builder: Render selected photos into a standards-compliant RIFF MJPEG .avi video with alpha crossfade transitions and multi-column PNG/PDF thumbnail contact sheets with SHA-256 verification.

SUPPORT & DONATE:
• Created by Thanh Nguyen — Support ongoing development: https://buymeacoffee.com/thanhnv128b