FlexWallet Icons are each a single icon (*.ico) file that contains the following image sizes: 16 x 16, 24 x 24, 32 x 32 and 48x48.
Whenever an appropriate size icon will be chosen from this list to display within the views.
Every *.ico file that you create must have these four different image sizes included within it. FlexWallet makes use of all of these sizes to display the icon in different places.
Once you have created an icon file, copy it to your device and place it in the \Program Files\FlexWallet\Custom Icons folder.