To handle images that can change from page to page based on content, use code block logic to set a file name in a variable, then reference that variable as an expression in an image command. For example:

prepage {
# use different image for each company
if compno$="1" then logo$="logo1.pcl"
if compno$="Z" then logo$="logoz.pcl"

image 1,1,20,10,{logo$}

Note that the variable can be null ("") in order to suppress the printing of the image.