I am not familiar with this specific collection but at the beginning of the 20th century "saving" the missions was a hot topic.
Your email does not make it clear whether the supplement provides details on the artist(s) which would be a key consideration. Also I know from personal experience that newspaper material does not scan well, even with the best of equipment. It produces an image that is useful for web viewing but impossible to turn into a real "print" of any quality or that would have value, and allow you to make something of this collection.
I suspect that the Chronicle has the originals in its archives. You should contact them for additional information and determine the availability (and cost) of authentic prints. These will be off copyright if you had the originals but may be subject to new restrictions in any reprint they might provide. You might also check to see that you can find in one of the historic newspaper archives and see what they would charge for the copies you already have.
There are literally hundreds and hundreds of paintings, photographs, lithographs and other renditions of the missions - some incredibly good (the paintings of Deakin, for example) others of more limited value and appeal. This is also true of late 19th and early 20th century photographs. Most of these are already in the public domain.