Does skybox have to have specific dimensions?

[Szuran]

So skyboxes are of certain size, and they are multiplied also a certain amount of times to "wrap around" the level when you look around. Can I make the texture wider so it's less repeated when doing a 360?

[andrewj]

Make the texture 1024 units wide and it will not repeat.

 

TNT Evilution and Plutonia Experiment IWADs have skies like this.