There are Skins of various sizes and formats. Typically, 800x600 and 848x480 are the most popular formats on CarPCs.. It is important to compare the size of the skin you want to use with the resolution of your monitor. By using a skin of the same size of your monitor's resolution, you can be sure that you will see exactly what the Skin's Author meant for you to see. But since it's not always possible to use the one skin we like best in the resolution you like best:

Adjusting the Skin's Size to your Screen's Size

This is a very simple adjustment, ant it should fix BOTH issues of when the skin doesn't fit and when the skin is not big enough:

-Open the GENERAL.INI file under your Skin's Folder
-Modify the SHOWWIDTH and SHOWHEIGHT settings to reflect your monitor's Width and Height (Resolution).
-Modify the Day/Night Gamma adjustments as you please (Optional)
-Save file

Note: When changing the size of display of a skin, it is possible to see distortion in the images (of you stretch it out of proportion). You should look for a skin that matches your monitor's aspect ratio for best results.

Note2: On the latest versions of RR, it is also possible to run RR at a different resolution than what you run your desktop applications.. all it takes is adding a line to RR.INI and RR will auto-switch the resolution when running to the specified setting:

resolution=WIDTHxHEIGHT[xBPP[xFREQ]]

Allows RR to run on specified resolution -- only the ones supported in control panel work.
Simply specify the Width and Height of the desired reslolution.
You can also specify the BPP (Bits per pixel) and the Refresh Rate (Frequency) of the display.
BPP Parameter is optional but you MUST specify it if you specify a Frequency.

Example1:
resolution=800x600

Example2:
resolution=800x600x32x60

Note that the Resolution change setting is also present in later versions of RRConfig.