I'm upgrading from 1.1 to 1.1.2 and I've downloaded just the upgrade package. I've seen that the styles/default/xenforo folder is full of elements and since I've modified a lot of images I would like to ask if there are changes in the images from 1.1 to 1.1.2 or if I can skip uploading the styles/default/xenforo folder
You should be making a new child style of the default style. Then in it change it to the new path. The new path should have a copy of all the default files and then you can change whatever you want. This will also mean you can change templates as you want without changing the default ones.