Scanning a document enables you to create an image of the document scanned. All scanned documents are in the digital image format. An image as all of us know occupies far more disk space when compared to text documents. When you choose to scan a document you have the option of doing so with many different resolutions. It depends upon the DPI that you choose when you scan the document. DPI refers to Dots per inches. The more the DPI, the larger is the document and the more the byte size. The first thing one must do if you want the scanned document to occupy less size would be to scan it with low DPI settings.
These scanned documents can then be compressed using any compression software. This reduces the byte size of the file and hence occupies less disk space and makes the file-management more manageable. In fact a set of scanned documents can be stored in a folder and the folder can be compressed using the compression software. How does compression work? What the software does is to store all the repeated and hence redundant information just once and when decompressed puts it back into its original space. Many files have this redundancy pattern, which is easily recognized by the software and this pattern is used to reduce the file size.
Another factor that could help reduce the size while scanning so that it makes the job of compression easier would be to scan it in the PDF optimization mode. A black and white or grayscale mode scanning would occupy far less space when compared to the RGB mode or the CMYK mode. But this really depends on what the scanned document is going to used for.
Now these scanned files that are compressed are small enough for web transfers. One can upload them and download them without having to use a broad bandwidth and also save time as well as money to a great extent.