
handle rotated screens (qpe-rotation) properly

optionally increase display backlight brightness when showing an image

feedback when loading an image (hourglass/progress bar)
- add element in pipeline that updates a progress bar when a
  new scanline arrives

popup menu in image window:
  allow loading unscaled image and pan around

middle (space) button can pop up menu in image view

circle part of an image to zoom in on it

Error handling - show meaningful error messages

fix empty functions in image pipeline classes

add ColorRemapper for gamma correction

thumbnails in ImageSet - probably needs multithreading

improve scaler accuracy (right now it accumulates fixed point roundoff errors)

thumbnail view

slideshow

preload large images when in view mode for fast switching to next image:
Keep a cache of images

support more image formats (e.g. PNG)
