wallpapers/image: Don't use QUrlQuery for preview
Original commit message(s)
- wallpapers/image: Don't use QUrlQuery for preview
It unfortunately doesn't do proper encoding, so let's just treat it as an opaque string.
Reason for the change
I added a wallpaper from a folder with a '+' in it. I could use it as wallpaper but it didn’t show a preview. This fixes this.