Import .gif?

Hello, I’m a new toonbommer and I read somewhere in this forum about importing gif instead of pdf. Is that possible? Do you know about other image formats that can be imported to TBS (got 4.5)? I basically want this kind of imports to serve as background for scenes. Please suggest software dowloads for processing images and convert formats (I can’t afford Photoshop right now).
Cheers,
Carlito

Regarding image formats:
Toon Boom Studio User Guide, page 100…

Regarding image editors:
Photoshop Elements 6…
Graphic Converter…
Gimp…
Pixelmator…
Choco Flop
Compositor…
Image Well…

Cheers
Nolan

Once again, thanks, pal.