I like Portable Network Graphics for bitmap images. PNGs improve on the GIF format and are presentable in either PDF or web-based formats.
I was dealing with a client’s data this week that included PNG graphics. The output quality was really poor but when I opened each graphic in a program like GIMP the image quality was fine. Turns out the source PNG files were corrupt. GIMP was fixing them before rendering them to the screen.
I found the corruption by using a Linux based command line utility called pngcheck.
Once I discovered the problem, I used another command line utility called pngcrush with a shell script to loop through all the graphics and fix the errors.
I love command lines!