I installed peek in Fedora 25 via the repo and it seems to work pretty good, does just about all I need it to do. Nice little utility.

Anyway, I'm not sure if it's a bug in the packaging but peek doesn't seem to have an icon. If you don't in fact have an icon yet I'd be happy to design you one if you'd like? I'm decent at icon design. I redesigned Pithos's icon a couple years ago. https://pithos.github.io/