Over time, we accumulated a bunch of exciting changes that impact app screenshots. AppStream guidelines were updated to include window decorations, tools are actually able to correctly capture the decorations and with libadwaita many apps already drastically changed their appearance.
Apart from that, we have a new Software design since 41 and apps.gnome.org exists. Therefore, outdated screenshots are more visible than ever before.
Long story short, we want to update all screenshots and as many as possible for GNOME 42. If your Core app’s screenshots are outdated, expect an MR soon. Please help us to get those changes in as quickly as possible. You can find all the details in the initiative issue.