Chapter 13
Working with Images

cpdf -image-resolution <minimum resolution> in.pdf [<range>]

13.1 Detecting Low-resolution Images

To list all images in the given range of pages which fall below a given resolution (in dots-per-inch), use the -image-resolution function:

cpdf -image-resolution 300 in.pdf [<range>]

2, /Im5, 531, 684, 149.935297, 150.138267  
2, /Im6, 184, 164, 149.999988, 150.458710  
2, /Im7, 171, 156, 149.999996, 150.579145  
2, /Im9, 65, 91, 149.999986, 151.071856  
2, /Im10, 94, 60, 149.999990, 152.284285  
2, /Im15, 184, 139, 149.960011, 150.672060  
4, /Im29, 53, 48, 149.970749, 151.616446

The format is page number, image name, x pixels, y pixels, x resolution, y resolution. The resolutions refer to the image’s effective resolution at point of use (taking account of scaling, rotation etc).

13.2 Removing an Image

To remove a particular image, find its name using -image-resolution with a sufficiently high resolution (so as to list all images), and then apply the -draft and -draft-remove-only operations from Section 15.1.