It should be the opposite, import the large kits (2048x2048) in the small section. They will be resized to 1024x1024, which will allow you to import more
If it still doesn't work, be sure to delete any large kits you don't need, as well as manager and stadium pics you don't need. If you edit often you might want to do a cleanup of your images, checking for any ones you don't need. You'll see you'll get some space
Thank you again. I'll try that.