Well a Google search can find the icon in question pretty fast. After that just convert the png with something like img2icns. Finally do Get Info on Mail and drag the icns file over the Mail icon.
Well a Google search can find the icon in question pretty fast. After that just convert the png with something like img2icns. Finally do Get Info on Mail and drag the icns file over the Mail icon.
I don't know how to convert...what do you mean convert the png with img2icns?
Edit:
Ok, I changed the mail icon from the google search from .png to .icns and dragged it over the original mail icon (the one in "get info") and there is only an image that says reads icns
Ok - download the icon from somewhere, then download img2icns. Once downloaded, launch it and drag the downloaded icon to where it says "drop images here". After that, select "icns" and save it to your desktop. Go to your Applications folder, find Mail.app and do Get Info. Now you should see all the info about Mail. In the top left corner there is a miniature icon. Drag the .icns file you just created with img2icns on there. The icon should change. You need to restart Mail to see changes in the Dock.