WOWSee is a best free image and PDF viewer for Windows10. Perfect support touch, mouse and keyboard. And WOWSee is the only app in the whole world that can sort/group images by color and has dynamic background color. And WOWSee also support group photos by GPS location.
WOWSee support animated GIF, and support slow and pause.
WOWSee support real-time increase contrast and sharpness, support real-time negative (reverse color) or grayscale image and PDF.
Shortcuts
Zoom: Ctrl + Mouse Wheel or Numeric Keypad +/-
Rotate: Shift + Mouse Wheel