Your friend is a very good friend! To make it a bit funnier, if I were you, I would ask your friend to prepare for 100 test images, and then I would start collecting images as many as I can within a time window - say 3 hours.
You see, I believe building a model won’t be a thing for you because you have already tried one, but building a good model that can withstand those unknown, challenging testing images is the real thing, and that experience to slowly evolve your model from good to better to best is the real thing.
Paul mentioned about course 2 and 3, but even if you just finish the videos under the sections of C3 W1 “Setting Up Your Goal”, “Comparing to Human-level Performance”, and C2 W2 “Error Analysis” and “Mismatched Training and Dev/Test Set” which are less than 2.5 hours in total, you will get the idea of how to evaluate and evolve your model. There is no pre-requisite to watch those videos, no maths except for basic arithmetrics, no difficult theories.
Imagine that you spend 3 hours to collect your first training set, 3 hours to shift your current code to it and implement the evaluations, 3 hours to train your model and evaluate it. 9 hours is sufficient for your first cycle of the evolution of your model. (Btw, you will see what I mean by cycle after finishing those course 3 videos)
Then you can continue on to the second cycle and it’s only going to take less time than the first because much of the 9 hour is one-time start-up cost. Let’s say the second cycle takes 3 hours, and three cycles total 9 + 3 + 3 = 15 hours, plus watching the course videos, it will be 18 hours. Therefore, it can be a 3-day project, and the most important take-away is the process of improvement, not necessarily to build a perfect model because even you are lucky to build a perfect model for hot-dogs, it doesn’t imply anything in the future. However, the improvement process is something you can bring over to the future.
This is just a suggestion and feel free to do it or not do it. If you want to do it but your friend is too busy to find some test images, or your friend wants the one who suggested this to contribute something too, let me know and I can collect 100 test images myself for you.
However, I will only share my images with you after you have finished the training