Can be raster files erased?

Hi,

I have a TomTom XXL classic IQ Edition 2GB, originally equipped with the "Western and Central Europe 2GB" map, and running the NC 9.510.
Because of the limited memory of this device, I have problems to use the current Wertern Europe map, so I'm trying to gain some space erasing unnecessary files.
I've already erased voice files of languages that I will never use, and gained around 32MB, but it is not enough.

Now I would like to know if I can erase a folder named "raster" wicht include several images of partial europe maps.

What is the purpose of these files? Just to see the images when exploring the map?
I've never used this function and I don't need it.
Can I erase this folder?

Thanks in advance for your support