Figure or Image?

[Michael84]

I'm proofreading a book for formal errors and I was just wondering what the normal term in English is for a series of images, pictures and photos?

They are called figures (abbreviation: fig.) in the book. That means every image/picture/drawing etc. has a small subtitle reading for example "Fig. 1: Device xy shown from top". The figures are numbered from 1 to n.

So what is the better term: images, figures or illustrations?

Thank you for your replies.

[SoothingDave]

"Figure" is normally used for this thing. Especially in technical writing or textbooks. "Illustration" is more like for full-page pictures found in children's books.