Try only uploading 3 or 4 pics at once. I have a turbo cable internet connection and I can only get away with uploading 4 or 5 pics at once. Try that first. I've never had a pic that was too big to upload unless you are talking pics that are 3 or 4 mb.
If you need to resize the pics and make them smaller, don't worry. It's easy to do.
Right click the pic and select the option to RESIZE PICTURES.
Now use the left menu to select a new size and then hit OK