Could you please tell me, what does DCIM in my sony ipod mean? how can i use that or when do i use that? please

Yes, that is the access to you picture files.

From WIKI:



Design rule for Camera File system (DCF) is a JEITA specification (number CP-3461) which defines a file format and file system for digital cameras, including the directory structure, file naming method, character set, file format, and metadata format. It is currently the de facto industry standard for digital still cameras. The file format of DCF is based on the Exif 2.2 specification.
The latest version of the standard is v 2.3.
The filesystem in a digital camera contains a DCIM (Digital Camera images) directory which contains possibly multiple subdirectories with names such as "123ABCDE", which consist of a unique directory number (in the range 100...999) and five alphanumeric characters, which may be freely chosen and often refer to a camera maker. These directories contain files with names such as "ABCD1234.JPG", which consist of four alphanumeric characters (often "DSC_" or "IMG_"), followed by a number. The file extension is "JPG" for Exif files and "THM" for Exif files that represent thumbnails. Other file formats use different extensions. Multiple files sharing a number (even if the file extension or the four alphanumeric characters are different) are considered related and form a DCF object.
For example, the files on a Nikon D40 are arranged according to the above specification. Thus, a card formatted by the camera will have a partition named "NIKOND40", with a subdirectory named "DCIM". This directory contains a subdirectory named by default "100NCD40", in which images are stored. images are named "DSC_xxxx", where xxxx represents the file's sequential number.
As this is an industry standard, similar directory structures and naming procedures can be found in most digital cameras.
[edit] AccessCamera file systems can usually be accessed by directly mounting them via the USB mass storage device class protocol, which exposes the file layout, whether DCF compliant or otherwise. Alternatively, and independent of DCF, files may be accessed via the Picture Transfer Protocol, which provides an object-oriented view and need not expose the file layout.
The file system layout is often opaque to users, as images are copied onto a computer or printer and the application deals with layout