When documents are shared online, they are usually converted to PDF files. The main reason many people use the PDF format is because they think its uneditable. Thus providing a sense of security against the end user changing the contents. Text in these files can still be copied to a word processor and edited. What is documents were converted into images ? That would make it much more harder to reproduce the content. Ofcourse there is OCR software that can read from images but other wise it seems more secure against an average user.
How to convert documents into image
ImagePrinter is a printer driver based on Microsoft’s universal printer driver. Using this software you can convert any document into an image. Common image formats like JPG, BMP, TIFF & even PDF is supported. It is available for all Windows operating systems.
All the features of the original file and contained in the image printed by the software. The program is lightweight on memory usage.