Let me try to clarify.
In AbanteCart, you do not need to upload images if you use Resource Library. You can drag batch of images from your computer into resource library window and images will be loaded into system and located in appropriate directory. This is build based on optimized directory and file naming approach.
This is much simpler than FTP approach.
Think of it as if you use itunes to organize your music. You do not ever deal with actual files.
If you want to upload images with traditional FTP (in case of large amount of images) you can still do that.
In this case, you need to use Import/Export tool (import in this case).
First you FTP images with some sort of organizational pattern and next you build CSV (excel) import file with your images
Hope this helps.