I need a tool to crop pictures:
- Allows me to select a zone (graphical user interface).
- Crops JPEG files with any loss of quality. This means that it only allows me to select a zone at particular points (iMCU boundary).
- When selecting the zone, show the real place at which it will crop (typically a few pixels off the place where my mouse is).
- Gratis, ideally open source.
- Works on Linux, callable via right-click on JPEG file from Nautilus
- Very fast to start, even when called for the first time since rebooting my computer.