Although the functionality to save documents as PDF files has been present in the newer versions of Microsoft Office, OpenOffice, LibreOffice and other applications, yet if you want to convert the images into PDF documents then you still have to look towards third party applications like PStill. PStill is a Windows application that can take almost any type of image file and save it as PS, XML or PDF document. In addition, it can also be used as a PDF printer enabling you to save PDF files from any Windows application.
The PStill has a small but feature loaded interface. You can drag and drop any of the supported files on the PStill window as the input files. It accepts all the major image types, postscript files and even some types of PDF documents as the input. You can drag and drop as many files as you want.
If you click on the More Options button, it will expand the window and show you many options that control how the output file is generated. You can choose compression options, text output options, post script interpreter options, script options, PDF page format and more. There are simply too many options for an ordinary user to configure and you may want to switch back to the less options screen by clicking on Less Options button.
After you have chosen an output file type (PDF, PS, EPS or XML), you can click on the Start Conversion button to start the conversion. The conversion takes only a few seconds and you are able to see the complete progress of the conversion process. When the conversion is complete, you can access the output file which is saved in the same folder as the input file itself.
Conclusion: PStill is a feature rich PDF conversion tool that can take all the major image types and convert them into PDF documents at the click of a button. It has many advanced options that give you full control over how the output file is produced.
You can download PStill from http://www.pstill.com/.