Details are missing on image display

[loitq07]

This is a minor issue that I think could be tweaked. As you can see the difference between Kobo OS, the image on Plato reader is missing a lot of details due to super low contrast.

No matter how I manually tweak the contrast and brightness bar, the image cannot get as good as the image of Kobo OS itself.

I don't know whether it can be fixed. Thanks for all your effort Bastien Dejean!