Icon Creation Question -- What format are custom shaped icons saved as?
I have Adobe Photoshop CS and Adobe Illustrator CS. I am assuming that one of those are able to create custom shaped icon format images for using on Mac folders.
I am able to save usable icons for folders as .psd format.
However, they are always square or rectangular, with a blank background around a non-square/non-rectangular image.
I'm not able (don't know how) to save icons as custom shapes that only appear as the custom shape when in use on a folder.
Examples
The .psd file in Photoshop is only the blue disc shape, but when it's saved, the white background is added by default.
.psd format image being used as icon on a Mac folder

Info box of the .psd image, when copying the small top-left icon image to paste over the top-left default folder icon image in the default folder's Info box

A randomly selected custom iPod icon that was downloaded from an Icon website, already on a folder

Info box of folder

I know how to use the Save for Web feature in Photoshop using the .png-24 selection which produces a transparent background, but that format doesn't work for icons.
What format(s) do I need to save images as to use as custom shaped icons on Mac folders?
A detailed reply would be very appreciated.
I am able to save usable icons for folders as .psd format.
However, they are always square or rectangular, with a blank background around a non-square/non-rectangular image.
I'm not able (don't know how) to save icons as custom shapes that only appear as the custom shape when in use on a folder.
Examples
The .psd file in Photoshop is only the blue disc shape, but when it's saved, the white background is added by default.
.psd format image being used as icon on a Mac folder

Info box of the .psd image, when copying the small top-left icon image to paste over the top-left default folder icon image in the default folder's Info box

A randomly selected custom iPod icon that was downloaded from an Icon website, already on a folder

Info box of folder

I know how to use the Save for Web feature in Photoshop using the .png-24 selection which produces a transparent background, but that format doesn't work for icons.
What format(s) do I need to save images as to use as custom shaped icons on Mac folders?
A detailed reply would be very appreciated.
Comments
Not a very detailed reply, but first you need to know that icons are built in 'layers' or masks. When you simply paste an image, a default mask is created that shows the surrounding background white.
What you need is a dedicated icon creator, such as the photoshop plug in 'Iconbuilder'...
http://iconfactory.com/software/iconbuilder
You can download a trial version.
Otherwise Google for 'Icon builders mac' to get a list of shareware builders that are cheaper.
OR, here...
http://interfacelift.com/icons-mac/software.php
Regards
Santa