My Pixma Pro-100 prints pages up to 19x13 inches (A3). However, one of my preferred print sizes is 13x9 (actually 8 and 2/3 inches), which matches the 3x2 aspect ratio typically used in cameras. Printing 2 of these on one sheet of 19x13 inch paper makes very optimal use of the paper. It also happens to fit nicely with inexpensive and easy to find glass that can be used in frames.
One of the features I especially like about the Pixma Pro-100 is the border-less printing. At present, the only way I've found to print 2 13x9 inch pictures on one sheet of 19x13 inch paper is to create a single image file that contains both images positioned as desired. It seems to me that there ought to be a much easier way to do it. One idea would be to feed the same sheet of 19x13 inch paper through the printer twice (i.e., once for each picture), where all that would be involved is turning the sheet around and feeding it in the opposite direction for the second printing operation. Another idea would be to cut the 19x13 inch sheets in half and then feed the resulting 13x9.5 inch sheets separately. Maybe there are other similar ideas I haven't thought of.
Unfortunately, it doesn't look like the Canon provided printer software is able to support either of these ideas. I'm hoping that someone with more expertise than me would know how to do this. It does seem to me like this is a sufficiently straightforward enough desire that I ought NOT be the only one who would like to do this.