First of all: thanks for this application. Great that it is open source - > I would like to contribute.

When scrolling through the images (large size) the image is first shown in bad quality and just after some time (after it's probably loaded from disk) it is displayed correctly. Now, because people usually navigate using arrow keys, the next respective the previous photo will be displayed next.

While a photo is shown, the application could jus cash the next ans previous photo, being ready when the user presses the arrow up/down key.

I could help implementing this.