Thanks for your reply. Allow me to elucidate.
These are two test images rendered from two php files - generateimage.php in php5 and generateimage.2.php in php4. The first line of both images should be a series of five random numbers expressed in random truetype fonts assigned from a folder. The lower five lines are in a default typestyle, listing the number and truetype font used to render them in the first line of the same image. The image on the right is from a working website with default php4. The image on the left is from a malfunctioning website with php5. Notice that the image on the left doesn't show the five numbers at the top of the image.
The images are rendering in test format - hence the five lines of default typestyle text below the first line of five numbers. When the image in not in test format, the five lines of text don't show - only the five numbers in one line, all at random axes, one after the other.
The images are set up identically on both sites. In fact the file was copied directly from one site to the other, along with the truetype fonts in their identical folders.
Again, I will be grateful for any help.