I would like to create a package of icons and offers them for download. But I have some questions relating to the creation of these icons software and the size that offers them. These icons can be used for any purpose, but mostly focuses on user interface in applications for desktop and smartphone or in website.
What is the appropriate software for creating icons? Adobe Illustrator or Adobe Photoshop? Or is there any better for this job?
From the point that these items will be generic, ie they can be used in an application or a site, even in some other project that you choose, what is the best size to be created?