Operator progress bar should display thumbnails while hovering
We need to see how hard it is for ffmpeg to create thumbnails. Either we do like youtube and create one big file with all thumbnails in a video, or we create as many thumbnails as possible.
Considering we have 15K+ songs, creating 15K x N thumbnail files seems unlikely.
So we should create a big image full of smaller images with a smaller resolution : which resolution?
Then we need code to make the thumbnailing work on the progressbar