Hi Nati, welcome to the forum.
You can use loadImage to load images in your sketch. In the example on that page they use 0, 0 to indicate the image’s location. You could replace these with global variables.
Without seeing any code it’s hard to give good advice however, so if you already made a start on your sketch don’t be shy to share it with us (or a minified version of it). Keep in mind that if you share the code and it uses an image, is that you add the image so we can test it.