This is a common question. The answer is yes. If you do it all at once, then it depends on the size of the images and your computer specs as there is so much your computer can handle. The question you need to answer is: do you need to have all those 20 images available at all times?
The best thing to do is for you to try to create a simple code where you attempt to load all the 20 images. If it works in your case, then you can implement it in your project. Otherwise, there will be some brainstorming ahead.
Kf