The best compromise for the size of icons for navigation devices is:
-size: 22 pixels by 22 pixels (for example on Tomtom, larger than 24 × 24 pixel icon cause a red-brown)
-number of colors: 16 (color depth: 4 bits)
From version 7 onwards of 'Tomtom application, it is possible to use another icon, larger (up to 48 × 48 pixels) that will be used in the' upper left corner when an alert occurs:
-44×44 pixel a 256 colori (8bit)
-bmp for Windows
The icon must always be based,22 x 22 pixel , however this.
Al ternatively you can use a little program for converting icons
Thanks [Only registered and activated users can see links. ]
It requires .NET 2.0 installed on your Windows PC to operate.
Thanks to those of poigps for more info