If you mean "What files can it read?" Then see this...
http://darkbasic.thegamecreators.com/?f=features
Quote: "
DarkBASIC natively supports the following Media File Formats...
Loaders / Savers for additional formats are available from 3rd
party developers or can be written yourself"
So whilst you can use the DBC command load bitmap,"xyz.bmp",1 to load bitmaps (which DBC "knows" how to use deal with, you could actually write code in your DBC program that moves through a file of a particular type and reads it in.
If you want to learn how a particular format works then
Google is your friend.
Sorry I can't post any code, but I am still learning about file input / output myself, at the moment, but thought I would share this nugget of knowledge
I'm sure Latch, Obese87 or the other experienced coders here may be able to shed some more light on this for you