Open images in background to speedup changing images
When I open image in directory which contains hundreads of 8k images (4912 × 7360) which takes ~5-10 MB, then when I change image with left/right keyboard key this operation took 1/2 second.
I'm using i7 4770(4/8), RX 570 and SSD drive, so computer is not so bad.
To speedup changing process, a few next and previous images should loaded in background and cached.
E.g.
User opens Image10.jpg -> App loads and shows Image10.jpg -> App loads in background Image5.jpg - Image9.jpg and Image11.jpg - Image14.jpg(few next and previous images) -> User press left key -> Almost instantly is showed Image9.jpg -> Image4.jpg is loaded in background -> Image14.jpg is removed from cache -> etc.