What are the technical requirements and reasonable master format for an iphone icon?

Question

I'm looking to commission an icon for an iphone app, and would like to provide the designers with the technical requirements. Also, as this may also be used as a logo for the website I'd like to be have a format that I can reuse and scale myself.

What technical requirements should I give to the designer and does apple have a publically linkable description of these? Is it simply 57x57 and 150x150 png or is there more to it?

Also, what is a reasonable, preferably open, scalable master format to request? I don't have photoshop and don't want to get it just for this.

Answer 1

The iPhone Human Interface Guidelines document about custom icons and images explains it in detail

Answer 2

My icon designers typically provide me with a vector file format version of my icon (usually an Illustrator file), a 512x512px TIFF file (which is submitted to Apple for use in the AppStore), and a 57x57px PNG (which is used as the actual application icon).

Also, If you want to get rid of the pre-rendered glossy bit you'll see on most iPhone apps' icons, go search for UIPrerenderedIcon, which is a flag you can set in your app's Info.plist file.

You don't need to go get Photoshop or Illustrator just for this, but you should have a 'master' file that you can keep in perpetuity in case you ever need another graphics designer to make modifications to the original icon.