Apparently the resources (splash and icon) is down (10:57 PM GMT+7).
Is there any other/alternative (preferably offline) way to generate the resources?
Despite of the high-reliability of the server, I think we still need a plan-B, don’t we? I’m kind of stuck now 
I also do Appcelerator development and this is a tool I have used in the past for generating resource files - http://ticons.fokkezb.nl/
you can use offline alternative binary that does the same job without internet plus it supports cross platform
https://github.com/harshzalavadiya/ionic-resource-generator
p.s. i am author of this tiny app
I had the same issue and I just tried https://github.com/helixhuang/ionic-resources , it’s an NPM package that uses graphicsmagick. It worked perfectly.
I haven’t tried ionic-resource-generator but it sounds great too.