I have some 20 different combinations of canonical pages featuring images in different categories. Is 100-150 words content okay for a page considering I use rel=canonical on their copies? I mean how's Google gonna take this? Does this affect the rankings? What are the othEr options?
This completely depends on what kind of performance you're expecting from the pages, what they need to rank for, how niche is the subject and what the competition is like.
100 - 150 words can give search engines enough to index with a high enough relevancy score to rank well, there's obviously many other factors to consider as well however.
The best approach would be to test, optimise a page for a target and see how it performs with 100 - 150 words. If it doesn't achieve what your goal, then try creating more depth to the content and promoting the page to gain inbound links to it.
Every case is a different and it's not really possible to elaborate on this further without knowing the exact circumstances.
There is a balance between keyword optimized and keyword stuffing.
100-150 words doesn't give search engines a lot to go on, but word count isn't everything.
Search engines also look for links, the quality of sites that link to you, etc.
So the answer is yes and no. There are too many factors at play. Make your site with your end user in mind, and the rest will follow.