I was looking for a lossless JPEG crop application and this one was very close to what I wanted, but it lacks some critical features to make this usable:

1, Pixel grid co-ordinates. I cannot accurately position the mouse cursor precisely where I need it to make a good crop without referring to X & Y co-ordinates.
2, Crop lock aspect ratio. If I want to crop at 1:1 (i.e. a square), or a custom aspect ratio.
3, Zoom pan. If I'm zoomed into a image to make an accurate crop, I would like to drag the cursor to the opposite end of an image and have the image pan within the application window.

Thanks.