JPG versus PDF for Document display

As we produce software for handling both JPEG and PDF files, we are often asked about which is better for displaying documents. So here I will try and sum up each and help you to decide.

JPG file

Is a single file with a public specification.
Is bit-mapped so will blur if you zoom in.
Cannot contain other content such as searchable text, links, video.
Is viewable on a huge range of tools.
Is very easy to alter its size, draw over, and manipulate.
Content cannot be encrypted

PDF file

Is a single file with a public specification.
Can contain vector content but may just be a bit-map. Can include lots of other content such as text, links, video.
Needs a PDF viewer to see. Most Operating Systems and browsers are able to do this now.
Can be edited but needs care.
Content and access can be set and contents encrypted.

In conclusion

PDF is a more complex and powerful file format which can have some additional benefits over just a JPEG image. In practice, JPEG is often enough for the job and many people use JPEG to display the contents of a PDF file (the most popular use for our Java PDF library is to convert PDF to Image).