In some cases, the unnumbered page is counted as a page but not numbered as such. If the unnumbered page is between 117 and 119, simply call it 118:

In book 4 of Paradise Lost, Satan observes Adam and Eve together in the garden. In William Blake’s illustration of this scene, the serpent is wrapped around Satan, who points suggestively at the first couple (Milton 118).

Work Cited

Milton, John. Paradise Lost. Edited by David Hawkes, Barnes and Noble Classics, 2004.

In some books, several images appear together. These are often printed on a different kind of paper from the surrounding text and not counted in the page numbering. In this case, provide a description of the image, or its title if it has one, in your prose. In the parenthetical citation, give the pages between which the section of images appears:

In a painting by William Shebbard, the playwright Thomas Killigrew sits at a desk on which are stacked several of his plays, including Claricilla and The Prisoners (Todd, between 246 and 247).

Work Cited

Todd, Janet. The Secret Life of Aphra Behn. Rutgers UP, 1996.

If the image is in one of these unnumbered sections and the image appears on a page directly opposite a numbered page, you may cite the opposite page, as follows:

In Earlham’s portrait of Anne Wharton, who corresponded with Behn, Wharton looks steadfastly at the viewer while gesturing mysteriously to a dark wood (Todd, opposite 247).

Work Cited

Todd, Janet. The Secret Life of Aphra Behn. Rutgers UP, 1996.