megaphar600 Hi! This is, unfortunately, a normal problem for newly uploaded sets. The system takes a bit of time to generate the icon previews, so they appear broken for a while. This is a known issue.
Usually, the icon previews get fixed by themselves if you wait a bit (usually, from a few hours to one day).
Other times, they remain broken. If you have been waiting for a long time and the icon previews still remain broken, please write to us at firstname.lastname@example.org and we'll fix them for you.