Articles pages: (The articles are just for graphic editing software engineer to accumulate knowledge to design better software for the end customers. They are not well-organized.)
Related knowledge of photo editing software:
Learn how to easily convert PNG to BMP, EPS, TGA, PSD, PDF, TIFF, GIF
Convert PNG To PDF software list
Purpose of the program png2pdf
Image To PDF COM/SDK description
The easiest way to convert your images into PDF
JPG BMP TIFF GIF Image to PDF Conversion
Convert image to pdf with Graphics2PDF